# Yahoo! UI Library

### AutoComplete Widget 2.5.1

Yahoo! UI Library > autocomplete > AutoComplete.js (source view)

Show Private Show Protected

     /**
     * The AutoComplete control provides the front-end logic for text-entry suggestion and
     * completion functionality.
     *
     * @module autocomplete
     * @requires yahoo, dom, event, datasource
     * @optional animation, connection, get
     * @namespace YAHOO.widget
     * @title AutoComplete Widget
     */

    /****************************************************************************/
    /****************************************************************************/
    /****************************************************************************/

    /**
     * The AutoComplete class provides the customizable functionality of a plug-and-play DHTML
     * auto completion widget.  Some key features:
     * <ul>
     * <li>Navigate with up/down arrow keys and/or mouse to pick a selection</li>
     * <li>The drop down container can "roll down" or "fly out" via configurable
     * animation</li>
     * <li>UI look-and-feel customizable through CSS, including container
     * attributes, borders, position, fonts, etc</li>
     * </ul>
     *
     * @class AutoComplete
     * @constructor
     * @param elInput {HTMLElement} DOM element reference of an input field.
     * @param elInput {String} String ID of an input field.
     * @param elContainer {HTMLElement} DOM element reference of an existing DIV.
     * @param elContainer {String} String ID of an existing DIV.
     * @param oDataSource {YAHOO.widget.DataSource} DataSource instance.
     * @param oConfigs {Object} (optional) Object literal of configuration params.
     */
    YAHOO.widget.AutoComplete = function(elInput,elContainer,oDataSource,oConfigs) {
        if(elInput && elContainer && oDataSource) {
            // Validate DataSource
            if(oDataSource instanceof YAHOO.widget.DataSource) {
                this.dataSource = oDataSource;
            }
            else {
                YAHOO.log("Could not instantiate AutoComplete due to an invalid DataSource", "error", this.toString());
                return;
            }

            // Validate input element
            if(YAHOO.util.Dom.inDocument(elInput)) {
                if(YAHOO.lang.isString(elInput)) {
                        this._sName = "instance" + YAHOO.widget.AutoComplete._nIndex + " " + elInput;
                        this._elTextbox = document.getElementById(elInput);
                }
                else {
                    this._sName = (elInput.id) ?
                        "instance" + YAHOO.widget.AutoComplete._nIndex + " " + elInput.id:
                        "instance" + YAHOO.widget.AutoComplete._nIndex;
                    this._elTextbox = elInput;
                }
                YAHOO.util.Dom.addClass(this._elTextbox, "yui-ac-input");
            }
            else {
                YAHOO.log("Could not instantiate AutoComplete due to an invalid input element", "error", this.toString());
                return;
            }

            // Validate container element
            if(YAHOO.util.Dom.inDocument(elContainer)) {
                if(YAHOO.lang.isString(elContainer)) {
                        this._elContainer = document.getElementById(elContainer);
                }
                else {
                    this._elContainer = elContainer;
                }
                if(this._elContainer.style.display == "none") {
                    YAHOO.log("The container may not display properly if display is set to \"none\" in CSS", "warn", this.toString());
                }

                // For skinning
                var elParent = this._elContainer.parentNode;
                var elTag = elParent.tagName.toLowerCase();
                if(elTag == "div") {
                    YAHOO.util.Dom.addClass(elParent, "yui-ac");
                }
                else {
                    YAHOO.log("Could not find the wrapper element for skinning", "warn", this.toString());
                }
            }
            else {
                YAHOO.log("Could not instantiate AutoComplete due to an invalid container element", "error", this.toString());
                return;
            }

            // Set any config params passed in to override defaults
            if(oConfigs && (oConfigs.constructor == Object)) {
                for(var sConfig in oConfigs) {
                    if(sConfig) {
                        this[sConfig] = oConfigs[sConfig];
                    }
                }
            }

            // Initialization sequence
            this._initContainer();
            this._initProps();
            this._initList();
            this._initContainerHelpers();

            // Set up events
            var oSelf = this;
            var elTextbox = this._elTextbox;
            // Events are actually for the content module within the container
            var elContent = this._elContent;

            // Dom events
            YAHOO.util.Event.addListener(elTextbox,"keyup",oSelf._onTextboxKeyUp,oSelf);
            YAHOO.util.Event.addListener(elTextbox,"keydown",oSelf._onTextboxKeyDown,oSelf);
            YAHOO.util.Event.addListener(elTextbox,"focus",oSelf._onTextboxFocus,oSelf);
            YAHOO.util.Event.addListener(elTextbox,"blur",oSelf._onTextboxBlur,oSelf);
            YAHOO.util.Event.addListener(elContent,"mouseover",oSelf._onContainerMouseover,oSelf);
            YAHOO.util.Event.addListener(elContent,"mouseout",oSelf._onContainerMouseout,oSelf);
            YAHOO.util.Event.addListener(elContent,"scroll",oSelf._onContainerScroll,oSelf);
            YAHOO.util.Event.addListener(elContent,"resize",oSelf._onContainerResize,oSelf);
            YAHOO.util.Event.addListener(elTextbox,"keypress",oSelf._onTextboxKeyPress,oSelf);
            YAHOO.util.Event.addListener(window,"unload",oSelf._onWindowUnload,oSelf);

            // Custom events
            this.textboxFocusEvent = new YAHOO.util.CustomEvent("textboxFocus", this);
            this.textboxKeyEvent = new YAHOO.util.CustomEvent("textboxKey", this);
            this.dataRequestEvent = new YAHOO.util.CustomEvent("dataRequest", this);
            this.dataReturnEvent = new YAHOO.util.CustomEvent("dataReturn", this);
            this.dataErrorEvent = new YAHOO.util.CustomEvent("dataError", this);
            this.containerExpandEvent = new YAHOO.util.CustomEvent("containerExpand", this);
            this.typeAheadEvent = new YAHOO.util.CustomEvent("typeAhead", this);
            this.itemMouseOverEvent = new YAHOO.util.CustomEvent("itemMouseOver", this);
            this.itemMouseOutEvent = new YAHOO.util.CustomEvent("itemMouseOut", this);
            this.itemArrowToEvent = new YAHOO.util.CustomEvent("itemArrowTo", this);
            this.itemArrowFromEvent = new YAHOO.util.CustomEvent("itemArrowFrom", this);
            this.itemSelectEvent = new YAHOO.util.CustomEvent("itemSelect", this);
            this.unmatchedItemSelectEvent = new YAHOO.util.CustomEvent("unmatchedItemSelect", this);
            this.selectionEnforceEvent = new YAHOO.util.CustomEvent("selectionEnforce", this);
            this.containerCollapseEvent = new YAHOO.util.CustomEvent("containerCollapse", this);
            this.textboxBlurEvent = new YAHOO.util.CustomEvent("textboxBlur", this);

            // Finish up
            elTextbox.setAttribute("autocomplete","off");
            YAHOO.widget.AutoComplete._nIndex++;
            YAHOO.log("AutoComplete initialized","info",this.toString());
        }
        // Required arguments were not found
        else {
            YAHOO.log("Could not instantiate AutoComplete due invalid arguments", "error", this.toString());
        }
    };

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public member variables
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * The DataSource object that encapsulates the data used for auto completion.
     * This object should be an inherited object from YAHOO.widget.DataSource.
     *
     * @property dataSource
     * @type YAHOO.widget.DataSource
     */
    YAHOO.widget.AutoComplete.prototype.dataSource = null;

    /**
     * Number of characters that must be entered before querying for results. A negative value
     * effectively turns off the widget. A value of 0 allows queries of null or empty string
     * values.
     *
     * @property minQueryLength
     * @type Number
     * @default 1
     */
    YAHOO.widget.AutoComplete.prototype.minQueryLength = 1;

    /**
     * Maximum number of results to display in results container.
     *
     * @property maxResultsDisplayed
     * @type Number
     * @default 10
     */
    YAHOO.widget.AutoComplete.prototype.maxResultsDisplayed = 10;

    /**
     * Number of seconds to delay before submitting a query request.  If a query
     * request is received before a previous one has completed its delay, the
     * previous request is cancelled and the new request is set to the delay.
     * Implementers should take care when setting this value very low (i.e., less
     * than 0.2) with low latency DataSources and the typeAhead feature enabled, as
     * fast typers may see unexpected behavior.
     *
     * @property queryDelay
     * @type Number
     * @default 0.2
     */
    YAHOO.widget.AutoComplete.prototype.queryDelay = 0.2;

    /**
     * Class name of a highlighted item within results container.
     *
     * @property highlightClassName
     * @type String
     * @default "yui-ac-highlight"
     */
    YAHOO.widget.AutoComplete.prototype.highlightClassName = "yui-ac-highlight";

    /**
     * Class name of a pre-highlighted item within results container.
     *
     * @property prehighlightClassName
     * @type String
     */
    YAHOO.widget.AutoComplete.prototype.prehighlightClassName = null;

    /**
     * Query delimiter. A single character separator for multiple delimited
     * selections. Multiple delimiter characteres may be defined as an array of
     * strings. A null value or empty string indicates that query results cannot
     * be delimited. This feature is not recommended if you need forceSelection to
     * be true.
     *
     * @property delimChar
     * @type String | String[]
     */
    YAHOO.widget.AutoComplete.prototype.delimChar = null;

    /**
     * Whether or not the first item in results container should be automatically highlighted
     * on expand.
     *
     * @property autoHighlight
     * @type Boolean
     * @default true
     */
    YAHOO.widget.AutoComplete.prototype.autoHighlight = true;

    /**
     * Whether or not the input field should be automatically updated
     * with the first query result as the user types, auto-selecting the substring
     * that the user has not typed.
     *
     * @property typeAhead
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.typeAhead = false;

    /**
     * Whether or not to animate the expansion/collapse of the results container in the
     * horizontal direction.
     *
     * @property animHoriz
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.animHoriz = false;

    /**
     * Whether or not to animate the expansion/collapse of the results container in the
     * vertical direction.
     *
     * @property animVert
     * @type Boolean
     * @default true
     */
    YAHOO.widget.AutoComplete.prototype.animVert = true;

    /**
     * Speed of container expand/collapse animation, in seconds..
     *
     * @property animSpeed
     * @type Number
     * @default 0.3
     */
    YAHOO.widget.AutoComplete.prototype.animSpeed = 0.3;

    /**
     * Whether or not to force the user's selection to match one of the query
     * results. Enabling this feature essentially transforms the input field into a
     * &lt;select&gt; field. This feature is not recommended with delimiter character(s)
     * defined.
     *
     * @property forceSelection
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.forceSelection = false;

    /**
     * Whether or not to allow browsers to cache user-typed input in the input
     * field. Disabling this feature will prevent the widget from setting the
     * autocomplete="off" on the input field. When autocomplete="off"
     * and users click the back button after form submission, user-typed input can
     * be prefilled by the browser from its cache. This caching of user input may
     * not be desired for sensitive data, such as credit card numbers, in which
     * case, implementers should consider setting allowBrowserAutocomplete to false.
     *
     * @property allowBrowserAutocomplete
     * @type Boolean
     * @default true
     */
    YAHOO.widget.AutoComplete.prototype.allowBrowserAutocomplete = true;

    /**
     * Whether or not the results container should always be displayed.
     * Enabling this feature displays the container when the widget is instantiated
     * and prevents the toggling of the container to a collapsed state.
     *
     * @property alwaysShowContainer
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.alwaysShowContainer = false;

    /**
     * Whether or not to use an iFrame to layer over Windows form elements in
     * IE. Set to true only when the results container will be on top of a
     * &lt;select&gt; field in IE and thus exposed to the IE z-index bug (i.e.,
     * 5.5 < IE < 7).
     *
     * @property useIFrame
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.useIFrame = false;

    /**
     * Whether or not the results container should have a shadow.
     *
     * @property useShadow
     * @type Boolean
     * @default false
     */
    YAHOO.widget.AutoComplete.prototype.useShadow = false;

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public methods
    //
    /////////////////////////////////////////////////////////////////////////////

     /**
     * Public accessor to the unique name of the AutoComplete instance.
     *
     * @method toString
     * @return {String} Unique name of the AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.toString = function() {
        return "AutoComplete " + this._sName;
    };

     /**
     * Returns true if container is in an expanded state, false otherwise.
     *
     * @method isContainerOpen
     * @return {Boolean} Returns true if container is in an expanded state, false otherwise.
     */
    YAHOO.widget.AutoComplete.prototype.isContainerOpen = function() {
        return this._bContainerOpen;
    };

    /**
     * Public accessor to the internal array of DOM &lt;li&gt; elements that
     * display query results within the results container.
     *
     * @method getListItems
     * @return {HTMLElement[]} Array of &lt;li&gt; elements within the results container.
     */
    YAHOO.widget.AutoComplete.prototype.getListItems = function() {
        return this._aListItems;
    };

    /**
     * Public accessor to the data held in an &lt;li&gt; element of the
     * results container.
     *
     * @method getListItemData
     * @return {Object | Object[]} Object or array of result data or null
     */
    YAHOO.widget.AutoComplete.prototype.getListItemData = function(oListItem) {
        if(oListItem._oResultData) {
            return oListItem._oResultData;
        }
        else {
            return false;
        }
    };

    /**
     * Sets HTML markup for the results container header. This markup will be
     * inserted within a &lt;div&gt; tag with a class of "yui-ac-hd".
     *
     * @method setHeader
     * @param sHeader {String} HTML markup for results container header.
     */
    YAHOO.widget.AutoComplete.prototype.setHeader = function(sHeader) {
        if(this._elHeader) {
            var elHeader = this._elHeader;
            if(sHeader) {
                elHeader.innerHTML = sHeader;
                elHeader.style.display = "block";
            }
            else {
                elHeader.innerHTML = "";
                elHeader.style.display = "none";
            }
        }
    };

    /**
     * Sets HTML markup for the results container footer. This markup will be
     * inserted within a &lt;div&gt; tag with a class of "yui-ac-ft".
     *
     * @method setFooter
     * @param sFooter {String} HTML markup for results container footer.
     */
    YAHOO.widget.AutoComplete.prototype.setFooter = function(sFooter) {
        if(this._elFooter) {
            var elFooter = this._elFooter;
            if(sFooter) {
                    elFooter.innerHTML = sFooter;
                    elFooter.style.display = "block";
            }
            else {
                elFooter.innerHTML = "";
                elFooter.style.display = "none";
            }
        }
    };

    /**
     * Sets HTML markup for the results container body. This markup will be
     * inserted within a &lt;div&gt; tag with a class of "yui-ac-bd".
     *
     * @method setBody
     * @param sBody {String} HTML markup for results container body.
     */
    YAHOO.widget.AutoComplete.prototype.setBody = function(sBody) {
        if(this._elBody) {
            var elBody = this._elBody;
            if(sBody) {
                    elBody.innerHTML = sBody;
                    elBody.style.display = "block";
                    elBody.style.display = "block";
            }
            else {
                elBody.innerHTML = "";
                elBody.style.display = "none";
            }
            this._maxResultsDisplayed = 0;
        }
    };

    /**
     * Overridable method that converts a result item object into HTML markup
     * for display. Return data values are accessible via the oResultItem object,
     * and the key return value will always be oResultItem[0]. Markup will be
     * displayed within &lt;li&gt; element tags in the container.
     *
     * @method formatResult
     * @param oResultItem {Object} Result item representing one query result. Data is held in an array.
     * @param sQuery {String} The current query string.
     * @return {String} HTML markup of formatted result data.
     */
    YAHOO.widget.AutoComplete.prototype.formatResult = function(oResultItem, sQuery) {
        var sResult = oResultItem[0];
        if(sResult) {
            return sResult;
        }
        else {
            return "";
        }
    };

    /**
     * Overridable method called before container expands allows implementers to access data
     * and DOM elements.
     *
     * @method doBeforeExpandContainer
     * @param elTextbox {HTMLElement} The text input box.
     * @param elContainer {HTMLElement} The container element.
     * @param sQuery {String} The query string.
     * @param aResults {Object[]}  An array of query results.
     * @return {Boolean} Return true to continue expanding container, false to cancel the expand.
     */
    YAHOO.widget.AutoComplete.prototype.doBeforeExpandContainer = function(elTextbox, elContainer, sQuery, aResults) {
        return true;
    };

    /**
     * Makes query request to the DataSource.
     *
     * @method sendQuery
     * @param sQuery {String} Query string.
     */
    YAHOO.widget.AutoComplete.prototype.sendQuery = function(sQuery) {
        this._sendQuery(sQuery);
    };

    /**
     * Overridable method gives implementers access to the query before it gets sent.
     *
     * @method doBeforeSendQuery
     * @param sQuery {String} Query string.
     * @return {String} Query string.
     */
    YAHOO.widget.AutoComplete.prototype.doBeforeSendQuery = function(sQuery) {
        return sQuery;
    };

    /**
     * Nulls out the entire AutoComplete instance and related objects, removes attached
     * event listeners, and clears out DOM elements inside the container. After
     * calling this method, the instance reference should be expliclitly nulled by
     * implementer, as in myDataTable = null. Use with caution!
     *
     * @method destroy
     */
    YAHOO.widget.AutoComplete.prototype.destroy = function() {
        var instanceName = this.toString();
        var elInput = this._elTextbox;
        var elContainer = this._elContainer;

        // Unhook custom events
        this.textboxFocusEvent.unsubscribeAll();
        this.textboxKeyEvent.unsubscribeAll();
        this.dataRequestEvent.unsubscribeAll();
        this.dataReturnEvent.unsubscribeAll();
        this.dataErrorEvent.unsubscribeAll();
        this.containerExpandEvent.unsubscribeAll();
        this.typeAheadEvent.unsubscribeAll();
        this.itemMouseOverEvent.unsubscribeAll();
        this.itemMouseOutEvent.unsubscribeAll();
        this.itemArrowToEvent.unsubscribeAll();
        this.itemArrowFromEvent.unsubscribeAll();
        this.itemSelectEvent.unsubscribeAll();
        this.unmatchedItemSelectEvent.unsubscribeAll();
        this.selectionEnforceEvent.unsubscribeAll();
        this.containerCollapseEvent.unsubscribeAll();
        this.textboxBlurEvent.unsubscribeAll();

        // Unhook DOM events
        YAHOO.util.Event.purgeElement(elInput, true);
        YAHOO.util.Event.purgeElement(elContainer, true);

        // Remove DOM elements
        elContainer.innerHTML = "";

        // Null out objects
        for(var key in this) {
            if(YAHOO.lang.hasOwnProperty(this, key)) {
                this[key] = null;
            }
        }

        YAHOO.log("AutoComplete instance destroyed: " + instanceName);
    };

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public events
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Fired when the input field receives focus.
     *
     * @event textboxFocusEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.textboxFocusEvent = null;

    /**
     * Fired when the input field receives key input.
     *
     * @event textboxKeyEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param nKeycode {Number} The keycode number.
     */
    YAHOO.widget.AutoComplete.prototype.textboxKeyEvent = null;

    /**
     * Fired when the AutoComplete instance makes a query to the DataSource.
     *
     * @event dataRequestEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param sQuery {String} The query string.
     */
    YAHOO.widget.AutoComplete.prototype.dataRequestEvent = null;

    /**
     * Fired when the AutoComplete instance receives query results from the data
     * source.
     *
     * @event dataReturnEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param sQuery {String} The query string.
     * @param aResults {Object[]} Results array.
     */
    YAHOO.widget.AutoComplete.prototype.dataReturnEvent = null;

    /**
     * Fired when the AutoComplete instance does not receive query results from the
     * DataSource due to an error.
     *
     * @event dataErrorEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param sQuery {String} The query string.
     */
    YAHOO.widget.AutoComplete.prototype.dataErrorEvent = null;

    /**
     * Fired when the results container is expanded.
     *
     * @event containerExpandEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.containerExpandEvent = null;

    /**
     * Fired when the input field has been prefilled by the type-ahead
     * feature.
     *
     * @event typeAheadEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param sQuery {String} The query string.
     * @param sPrefill {String} The prefill string.
     */
    YAHOO.widget.AutoComplete.prototype.typeAheadEvent = null;

    /**
     * Fired when result item has been moused over.
     *
     * @event itemMouseOverEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param elItem {HTMLElement} The &lt;li&gt element item moused to.
     */
    YAHOO.widget.AutoComplete.prototype.itemMouseOverEvent = null;

    /**
     * Fired when result item has been moused out.
     *
     * @event itemMouseOutEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param elItem {HTMLElement} The &lt;li&gt; element item moused from.
     */
    YAHOO.widget.AutoComplete.prototype.itemMouseOutEvent = null;

    /**
     * Fired when result item has been arrowed to.
     *
     * @event itemArrowToEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param elItem {HTMLElement} The &lt;li&gt; element item arrowed to.
     */
    YAHOO.widget.AutoComplete.prototype.itemArrowToEvent = null;

    /**
     * Fired when result item has been arrowed away from.
     *
     * @event itemArrowFromEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param elItem {HTMLElement} The &lt;li&gt; element item arrowed from.
     */
    YAHOO.widget.AutoComplete.prototype.itemArrowFromEvent = null;

    /**
     * Fired when an item is selected via mouse click, ENTER key, or TAB key.
     *
     * @event itemSelectEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @param elItem {HTMLElement} The selected &lt;li&gt; element item.
     * @param oData {Object} The data returned for the item, either as an object,
     * or mapped from the schema into an array.
     */
    YAHOO.widget.AutoComplete.prototype.itemSelectEvent = null;

    /**
     * Fired when a user selection does not match any of the displayed result items.
     *
     * @event unmatchedItemSelectEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.unmatchedItemSelectEvent = null;

    /**
     * Fired if forceSelection is enabled and the user's input has been cleared
     * because it did not match one of the returned query results.
     *
     * @event selectionEnforceEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.selectionEnforceEvent = null;

    /**
     * Fired when the results container is collapsed.
     *
     * @event containerCollapseEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.containerCollapseEvent = null;

    /**
     * Fired when the input field loses focus.
     *
     * @event textboxBlurEvent
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     */
    YAHOO.widget.AutoComplete.prototype.textboxBlurEvent = null;

    /////////////////////////////////////////////////////////////////////////////
    //
    // Private member variables
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Internal class variable to index multiple AutoComplete instances.
     *
     * @property _nIndex
     * @type Number
     * @default 0
     * @private
     */
    YAHOO.widget.AutoComplete._nIndex = 0;

    /**
     * Name of AutoComplete instance.
     *
     * @property _sName
     * @type String
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._sName = null;

    /**
     * Text input field DOM element.
     *
     * @property _elTextbox
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elTextbox = null;

    /**
     * Container DOM element.
     *
     * @property _elContainer
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elContainer = null;

    /**
     * Reference to content element within container element.
     *
     * @property _elContent
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elContent = null;

    /**
     * Reference to header element within content element.
     *
     * @property _elHeader
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elHeader = null;

    /**
     * Reference to body element within content element.
     *
     * @property _elBody
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elBody = null;

    /**
     * Reference to footer element within content element.
     *
     * @property _elFooter
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elFooter = null;

    /**
     * Reference to shadow element within container element.
     *
     * @property _elShadow
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elShadow = null;

    /**
     * Reference to iframe element within container element.
     *
     * @property _elIFrame
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._elIFrame = null;

    /**
     * Whether or not the input field is currently in focus. If query results come back
     * but the user has already moved on, do not proceed with auto complete behavior.
     *
     * @property _bFocused
     * @type Boolean
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._bFocused = true;

    /**
     * Animation instance for container expand/collapse.
     *
     * @property _oAnim
     * @type Boolean
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._oAnim = null;

    /**
     * Whether or not the results container is currently open.
     *
     * @property _bContainerOpen
     * @type Boolean
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._bContainerOpen = false;

    /**
     * Whether or not the mouse is currently over the results
     * container. This is necessary in order to prevent clicks on container items
     * from being text input field blur events.
     *
     * @property _bOverContainer
     * @type Boolean
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._bOverContainer = false;

    /**
     * Array of &lt;li&gt; elements references that contain query results within the
     * results container.
     *
     * @property _aListItems
     * @type HTMLElement[]
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._aListItems = null;

    /**
     * Number of &lt;li&gt; elements currently displayed in results container.
     *
     * @property _nDisplayedItems
     * @type Number
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._nDisplayedItems = 0;

    /**
     * Internal count of &lt;li&gt; elements displayed and hidden in results container.
     *
     * @property _maxResultsDisplayed
     * @type Number
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._maxResultsDisplayed = 0;

    /**
     * Current query string
     *
     * @property _sCurQuery
     * @type String
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._sCurQuery = null;

    /**
     * Past queries this session (for saving delimited queries).
     *
     * @property _sSavedQuery
     * @type String
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._sSavedQuery = null;

    /**
     * Pointer to the currently highlighted &lt;li&gt; element in the container.
     *
     * @property _oCurItem
     * @type HTMLElement
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._oCurItem = null;

    /**
     * Whether or not an item has been selected since the container was populated
     * with results. Reset to false by _populateList, and set to true when item is
     * selected.
     *
     * @property _bItemSelected
     * @type Boolean
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._bItemSelected = false;

    /**
     * Key code of the last key pressed in textbox.
     *
     * @property _nKeyCode
     * @type Number
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._nKeyCode = null;

    /**
     * Delay timeout ID.
     *
     * @property _nDelayID
     * @type Number
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._nDelayID = -1;

    /**
     * Src to iFrame used when useIFrame = true. Supports implementations over SSL
     * as well.
     *
     * @property _iFrameSrc
     * @type String
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._iFrameSrc = "javascript:false;";

    /**
     * For users typing via certain IMEs, queries must be triggered by intervals,
     * since key events yet supported across all browsers for all IMEs.
     *
     * @property _queryInterval
     * @type Object
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._queryInterval = null;

    /**
     * Internal tracker to last known textbox value, used to determine whether or not
     * to trigger a query via interval for certain IME users.
     *
     * @event _sLastTextboxValue
     * @type String
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._sLastTextboxValue = null;

    /////////////////////////////////////////////////////////////////////////////
    //
    // Private methods
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Updates and validates latest public config properties.
     *
     * @method __initProps
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._initProps = function() {
        // Correct any invalid values
        var minQueryLength = this.minQueryLength;
        if(!YAHOO.lang.isNumber(minQueryLength)) {
            this.minQueryLength = 1;
        }
        var maxResultsDisplayed = this.maxResultsDisplayed;
        if(!YAHOO.lang.isNumber(maxResultsDisplayed) || (maxResultsDisplayed < 1)) {
            this.maxResultsDisplayed = 10;
        }
        var queryDelay = this.queryDelay;
        if(!YAHOO.lang.isNumber(queryDelay) || (queryDelay < 0)) {
            this.queryDelay = 0.2;
        }
        var delimChar = this.delimChar;
        if(YAHOO.lang.isString(delimChar) && (delimChar.length > 0)) {
            this.delimChar = [delimChar];
        }
        else if(!YAHOO.lang.isArray(delimChar)) {
            this.delimChar = null;
        }
        var animSpeed = this.animSpeed;
        if((this.animHoriz || this.animVert) && YAHOO.util.Anim) {
            if(!YAHOO.lang.isNumber(animSpeed) || (animSpeed < 0)) {
                this.animSpeed = 0.3;
            }
            if(!this._oAnim ) {
                this._oAnim = new YAHOO.util.Anim(this._elContent, {}, this.animSpeed);
            }
            else {
                this._oAnim.duration = this.animSpeed;
            }
        }
        if(this.forceSelection && delimChar) {
            YAHOO.log("The forceSelection feature has been enabled with delimChar defined.","warn", this.toString());
        }
    };

    /**
     * Initializes the results container helpers if they are enabled and do
     * not exist
     *
     * @method _initContainerHelpers
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._initContainerHelpers = function() {
        if(this.useShadow && !this._elShadow) {
            var elShadow = document.createElement("div");
            elShadow.className = "yui-ac-shadow";
            this._elShadow = this._elContainer.appendChild(elShadow);
        }
        if(this.useIFrame && !this._elIFrame) {
            var elIFrame = document.createElement("iframe");
            elIFrame.src = this._iFrameSrc;
            elIFrame.frameBorder = 0;
            elIFrame.scrolling = "no";
            elIFrame.style.position = "absolute";
            elIFrame.style.width = "100%";
            elIFrame.style.height = "100%";
            elIFrame.tabIndex = -1;
            this._elIFrame = this._elContainer.appendChild(elIFrame);
        }
    };

    /**
     * Initializes the results container once at object creation
     *
     * @method _initContainer
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._initContainer = function() {
        YAHOO.util.Dom.addClass(this._elContainer, "yui-ac-container");

        if(!this._elContent) {
            // The elContent div helps size the iframe and shadow properly
            var elContent = document.createElement("div");
            elContent.className = "yui-ac-content";
            elContent.style.display = "none";
            this._elContent = this._elContainer.appendChild(elContent);

            var elHeader = document.createElement("div");
            elHeader.className = "yui-ac-hd";
            elHeader.style.display = "none";
            this._elHeader = this._elContent.appendChild(elHeader);

            var elBody = document.createElement("div");
            elBody.className = "yui-ac-bd";
            this._elBody = this._elContent.appendChild(elBody);

            var elFooter = document.createElement("div");
            elFooter.className = "yui-ac-ft";
            elFooter.style.display = "none";
            this._elFooter = this._elContent.appendChild(elFooter);
        }
        else {
            YAHOO.log("Could not initialize the container","warn",this.toString());
        }
    };

    /**
     * Clears out contents of container body and creates up to
     * YAHOO.widget.AutoComplete#maxResultsDisplayed &lt;li&gt; elements in an
     * &lt;ul&gt; element.
     *
     * @method _initList
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._initList = function() {
        this._aListItems = [];
        while(this._elBody.hasChildNodes()) {
            var oldListItems = this.getListItems();
            if(oldListItems) {
                for(var oldi = oldListItems.length-1; oldi >= 0; oldi--) {
                    oldListItems[oldi] = null;
                }
            }
            this._elBody.innerHTML = "";
        }

        var oList = document.createElement("ul");
        oList = this._elBody.appendChild(oList);
        for(var i=0; i<this.maxResultsDisplayed; i++) {
            var oItem = document.createElement("li");
            oItem = oList.appendChild(oItem);
            this._aListItems[i] = oItem;
            this._initListItem(oItem, i);
        }
        this._maxResultsDisplayed = this.maxResultsDisplayed;
    };

    /**
     * Initializes each &lt;li&gt; element in the container list.
     *
     * @method _initListItem
     * @param oItem {HTMLElement} The &lt;li&gt; DOM element.
     * @param nItemIndex {Number} The index of the element.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._initListItem = function(oItem, nItemIndex) {
        var oSelf = this;
        oItem.style.display = "none";
        oItem._nItemIndex = nItemIndex;

        oItem.mouseover = oItem.mouseout = oItem.onclick = null;
        YAHOO.util.Event.addListener(oItem,"mouseover",oSelf._onItemMouseover,oSelf);
        YAHOO.util.Event.addListener(oItem,"mouseout",oSelf._onItemMouseout,oSelf);
        YAHOO.util.Event.addListener(oItem,"click",oSelf._onItemMouseclick,oSelf);
    };

    /**
     * Enables interval detection for  Korean IME support.
     *
     * @method _onIMEDetected
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onIMEDetected = function(oSelf) {
        oSelf._enableIntervalDetection();
    };

    /**
     * Enables query triggers based on text input detection by intervals (rather
     * than by key events).
     *
     * @method _enableIntervalDetection
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._enableIntervalDetection = function() {
        var currValue = this._elTextbox.value;
        var lastValue = this._sLastTextboxValue;
        if(currValue != lastValue) {
            this._sLastTextboxValue = currValue;
            this._sendQuery(currValue);
        }
    };

    /**
     * Cancels text input detection by intervals.
     *
     * @method _cancelIntervalDetection
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._cancelIntervalDetection = function(oSelf) {
        if(oSelf._queryInterval) {
            clearInterval(oSelf._queryInterval);
        }
    };

    /**
     * Whether or not key is functional or should be ignored. Note that the right
     * arrow key is NOT an ignored key since it triggers queries for certain intl
     * charsets.
     *
     * @method _isIgnoreKey
     * @param nKeycode {Number} Code of key pressed.
     * @return {Boolean} True if key should be ignored, false otherwise.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._isIgnoreKey = function(nKeyCode) {
        if((nKeyCode == 9) || (nKeyCode == 13)  || // tab, enter
                (nKeyCode == 16) || (nKeyCode == 17) || // shift, ctl
                (nKeyCode >= 18 && nKeyCode <= 20) || // alt,pause/break,caps lock
                (nKeyCode == 27) || // esc
                (nKeyCode >= 33 && nKeyCode <= 35) || // page up,page down,end
                /*(nKeyCode >= 36 && nKeyCode <= 38) || // home,left,up
                (nKeyCode == 40) || // down*/
                (nKeyCode >= 36 && nKeyCode <= 40) || // home,left,up, right, down
                (nKeyCode >= 44 && nKeyCode <= 45)) { // print screen,insert
            return true;
        }
        return false;
    };

    /**
     * Makes query request to the DataSource.
     *
     * @method _sendQuery
     * @param sQuery {String} Query string.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._sendQuery = function(sQuery) {
        // Widget has been effectively turned off
        if(this.minQueryLength == -1) {
            this._toggleContainer(false);
            YAHOO.log("Property minQueryLength is set to -1", "info", this.toString());
            return;
        }
        // Delimiter has been enabled
        var aDelimChar = (this.delimChar) ? this.delimChar : null;
        if(aDelimChar) {
            // Loop through all possible delimiters and find the latest one
            // A " " may be a false positive if they are defined as delimiters AND
            // are used to separate delimited queries
            var nDelimIndex = -1;
            for(var i = aDelimChar.length-1; i >= 0; i--) {
                var nNewIndex = sQuery.lastIndexOf(aDelimChar[i]);
                if(nNewIndex > nDelimIndex) {
                    nDelimIndex = nNewIndex;
                }
            }
            // If we think the last delimiter is a space (" "), make sure it is NOT
            // a false positive by also checking the char directly before it
            if(aDelimChar[i] == " ") {
                for (var j = aDelimChar.length-1; j >= 0; j--) {
                    if(sQuery[nDelimIndex - 1] == aDelimChar[j]) {
                        nDelimIndex--;
                        break;
                    }
                }
            }
            // A delimiter has been found so extract the latest query
            if(nDelimIndex > -1) {
                var nQueryStart = nDelimIndex + 1;
                // Trim any white space from the beginning...
                while(sQuery.charAt(nQueryStart) == " ") {
                    nQueryStart += 1;
                }
                // ...and save the rest of the string for later
                this._sSavedQuery = sQuery.substring(0,nQueryStart);
                // Here is the query itself
                sQuery = sQuery.substr(nQueryStart);
            }
            else if(sQuery.indexOf(this._sSavedQuery) < 0){
                this._sSavedQuery = null;
            }
        }

        // Don't search queries that are too short
        if((sQuery && (sQuery.length < this.minQueryLength)) || (!sQuery && this.minQueryLength > 0)) {
            if(this._nDelayID != -1) {
                clearTimeout(this._nDelayID);
            }
            this._toggleContainer(false);
            YAHOO.log("Query \"" + sQuery + "\" is too short", "info", this.toString());
            return;
        }

        sQuery = encodeURIComponent(sQuery);
        this._nDelayID = -1;    // Reset timeout ID because request has been made
        sQuery = this.doBeforeSendQuery(sQuery);
        this.dataRequestEvent.fire(this, sQuery);
        YAHOO.log("Sending query \"" + sQuery + "\"", "info", this.toString());
        this.dataSource.getResults(this._populateList, sQuery, this);
    };

    /**
     * Populates the array of &lt;li&gt; elements in the container with query
     * results. This method is passed to YAHOO.widget.DataSource#getResults as a
     * callback function so results from the DataSource instance are returned to the
     * AutoComplete instance.
     *
     * @method _populateList
     * @param sQuery {String} The query string.
     * @param aResults {Object[]} An array of query result objects from the DataSource.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._populateList = function(sQuery, aResults, oSelf) {
        if(aResults === null) {
            oSelf.dataErrorEvent.fire(oSelf, sQuery);
        }
        if(!oSelf._bFocused || !aResults) {
            YAHOO.log("Could not populate list", "info", oSelf.toString());
            return;
        }

        var isOpera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
        var contentStyle = oSelf._elContent.style;
        contentStyle.width = (!isOpera) ? null : "";
        contentStyle.height = (!isOpera) ? null : "";

        var sCurQuery = decodeURIComponent(sQuery);
        oSelf._sCurQuery = sCurQuery;
        oSelf._bItemSelected = false;

        if(oSelf._maxResultsDisplayed != oSelf.maxResultsDisplayed) {
            oSelf._initList();
        }

        var nItems = Math.min(aResults.length,oSelf.maxResultsDisplayed);
        oSelf._nDisplayedItems = nItems;
        if(nItems > 0) {
            oSelf._initContainerHelpers();
            var aItems = oSelf._aListItems;

            // Fill items with data
            for(var i = nItems-1; i >= 0; i--) {
                var oItemi = aItems[i];
                var oResultItemi = aResults[i];
                oItemi.innerHTML = oSelf.formatResult(oResultItemi, sCurQuery);
                oItemi.style.display = "list-item";
                oItemi._sResultKey = oResultItemi[0];
                oItemi._oResultData = oResultItemi;

            }

            // Empty out remaining items if any
            for(var j = aItems.length-1; j >= nItems ; j--) {
                var oItemj = aItems[j];
                oItemj.innerHTML = null;
                oItemj.style.display = "none";
                oItemj._sResultKey = null;
                oItemj._oResultData = null;
            }

            // Expand the container
            var ok = oSelf.doBeforeExpandContainer(oSelf._elTextbox, oSelf._elContainer, sQuery, aResults);
            oSelf._toggleContainer(ok);

            if(oSelf.autoHighlight) {
                // Go to the first item
                var oFirstItem = aItems[0];
                oSelf._toggleHighlight(oFirstItem,"to");
                oSelf.itemArrowToEvent.fire(oSelf, oFirstItem);
                YAHOO.log("Arrowed to first item", "info", oSelf.toString());
                oSelf._typeAhead(oFirstItem,sQuery);
            }
            else {
                oSelf._oCurItem = null;
            }
        }
        else {
            oSelf._toggleContainer(false);
        }
        oSelf.dataReturnEvent.fire(oSelf, sQuery, aResults);
        YAHOO.log("Container populated with list items", "info", oSelf.toString());

    };

    /**
     * When forceSelection is true and the user attempts
     * leave the text input box without selecting an item from the query results,
     * the user selection is cleared.
     *
     * @method _clearSelection
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._clearSelection = function() {
        var sValue = this._elTextbox.value;
        var sChar = (this.delimChar) ? this.delimChar[0] : null;
        var nIndex = (sChar) ? sValue.lastIndexOf(sChar, sValue.length-2) : -1;
        if(nIndex > -1) {
            this._elTextbox.value = sValue.substring(0,nIndex);
        }
        else {
             this._elTextbox.value = "";
        }
        this._sSavedQuery = this._elTextbox.value;

        // Fire custom event
        this.selectionEnforceEvent.fire(this);
        YAHOO.log("Selection enforced", "info", this.toString());
    };

    /**
     * Whether or not user-typed value in the text input box matches any of the
     * query results.
     *
     * @method _textMatchesOption
     * @return {HTMLElement} Matching list item element if user-input text matches
     * a result, null otherwise.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._textMatchesOption = function() {
        var foundMatch = null;

        for(var i = this._nDisplayedItems-1; i >= 0 ; i--) {
            var oItem = this._aListItems[i];
            var sMatch = oItem._sResultKey.toLowerCase();
            if(sMatch == this._sCurQuery.toLowerCase()) {
                foundMatch = oItem;
                break;
            }
        }
        return(foundMatch);
    };

    /**
     * Updates in the text input box with the first query result as the user types,
     * selecting the substring that the user has not typed.
     *
     * @method _typeAhead
     * @param oItem {HTMLElement} The &lt;li&gt; element item whose data populates the input field.
     * @param sQuery {String} Query string.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._typeAhead = function(oItem, sQuery) {
        // Don't update if turned off
        if(!this.typeAhead || (this._nKeyCode == 8)) {
            return;
        }

        var elTextbox = this._elTextbox;
        var sValue = this._elTextbox.value; // any saved queries plus what user has typed

        // Don't update with type-ahead if text selection is not supported
        if(!elTextbox.setSelectionRange && !elTextbox.createTextRange) {
            return;
        }

        // Select the portion of text that the user has not typed
        var nStart = sValue.length;
        this._updateValue(oItem);
        var nEnd = elTextbox.value.length;
        this._selectText(elTextbox,nStart,nEnd);
        var sPrefill = elTextbox.value.substr(nStart,nEnd);
        this.typeAheadEvent.fire(this,sQuery,sPrefill);
        YAHOO.log("Typeahead occured with prefill string \"" + sPrefill + "\"", "info", this.toString());
    };

    /**
     * Selects text in the input field.
     *
     * @method _selectText
     * @param elTextbox {HTMLElement} Text input box element in which to select text.
     * @param nStart {Number} Starting index of text string to select.
     * @param nEnd {Number} Ending index of text selection.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._selectText = function(elTextbox, nStart, nEnd) {
        if(elTextbox.setSelectionRange) { // For Mozilla
            elTextbox.setSelectionRange(nStart,nEnd);
        }
        else if(elTextbox.createTextRange) { // For IE
            var oTextRange = elTextbox.createTextRange();
            oTextRange.moveStart("character", nStart);
            oTextRange.moveEnd("character", nEnd-elTextbox.value.length);
            oTextRange.select();
        }
        else {
            elTextbox.select();
        }
    };

    /**
     * Syncs results container with its helpers.
     *
     * @method _toggleContainerHelpers
     * @param bShow {Boolean} True if container is expanded, false if collapsed
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._toggleContainerHelpers = function(bShow) {
        var bFireEvent = false;
        var width = this._elContent.offsetWidth + "px";
        var height = this._elContent.offsetHeight + "px";

        if(this.useIFrame && this._elIFrame) {
            bFireEvent = true;
            if(bShow) {
                this._elIFrame.style.width = width;
                this._elIFrame.style.height = height;
            }
            else {
                this._elIFrame.style.width = 0;
                this._elIFrame.style.height = 0;
            }
        }
        if(this.useShadow && this._elShadow) {
            bFireEvent = true;
            if(bShow) {
                this._elShadow.style.width = width;
                this._elShadow.style.height = height;
            }
            else {
               this._elShadow.style.width = 0;
                this._elShadow.style.height = 0;
            }
        }
    };

    /**
     * Animates expansion or collapse of the container.
     *
     * @method _toggleContainer
     * @param bShow {Boolean} True if container should be expanded, false if container should be collapsed
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._toggleContainer = function(bShow) {
        var elContainer = this._elContainer;

        // Implementer has container always open so don't mess with it
        if(this.alwaysShowContainer && this._bContainerOpen) {
            return;
        }

        // Clear contents of container
        if(!bShow) {
            this._elContent.scrollTop = 0;
            var aItems = this._aListItems;

            if(aItems && (aItems.length > 0)) {
                for(var i = aItems.length-1; i >= 0 ; i--) {
                    aItems[i].style.display = "none";
                }
            }

            if(this._oCurItem) {
                this._toggleHighlight(this._oCurItem,"from");
            }

            this._oCurItem = null;
            this._nDisplayedItems = 0;
            this._sCurQuery = null;
        }

        // Container is already closed
        if(!bShow && !this._bContainerOpen) {
            this._elContent.style.display = "none";
            return;
        }

        // If animation is enabled...
        var oAnim = this._oAnim;
        if(oAnim && oAnim.getEl() && (this.animHoriz || this.animVert)) {
            // If helpers need to be collapsed, do it right away...
            // but if helpers need to be expanded, wait until after the container expands
            if(!bShow) {
                this._toggleContainerHelpers(bShow);
            }

            if(oAnim.isAnimated()) {
                oAnim.stop();
            }

            // Clone container to grab current size offscreen
            var oClone = this._elContent.cloneNode(true);
            elContainer.appendChild(oClone);
            oClone.style.top = "-9000px";
            oClone.style.display = "block";

            // Current size of the container is the EXPANDED size
            var wExp = oClone.offsetWidth;
            var hExp = oClone.offsetHeight;

            // Calculate COLLAPSED sizes based on horiz and vert anim
            var wColl = (this.animHoriz) ? 0 : wExp;
            var hColl = (this.animVert) ? 0 : hExp;

            // Set animation sizes
            oAnim.attributes = (bShow) ?
                {width: { to: wExp }, height: { to: hExp }} :
                {width: { to: wColl}, height: { to: hColl }};

            // If opening anew, set to a collapsed size...
            if(bShow && !this._bContainerOpen) {
                this._elContent.style.width = wColl+"px";
                this._elContent.style.height = hColl+"px";
            }
            // Else, set it to its last known size.
            else {
                this._elContent.style.width = wExp+"px";
                this._elContent.style.height = hExp+"px";
            }

            elContainer.removeChild(oClone);
            oClone = null;

        	var oSelf = this;
        	var onAnimComplete = function() {
                // Finish the collapse
        		oAnim.onComplete.unsubscribeAll();

                if(bShow) {
                    oSelf.containerExpandEvent.fire(oSelf);
                    YAHOO.log("Container expanded", "info", oSelf.toString());
                }
                else {
                    oSelf._elContent.style.display = "none";
                    oSelf.containerCollapseEvent.fire(oSelf);
                    YAHOO.log("Container collapsed", "info", oSelf.toString());
                }
                oSelf._toggleContainerHelpers(bShow);
         	};

            // Display container and animate it
            this._elContent.style.display = "block";
            oAnim.onComplete.subscribe(onAnimComplete);
            oAnim.animate();
            this._bContainerOpen = bShow;
        }
        // Else don't animate, just show or hide
        else {
            if(bShow) {
                this._elContent.style.display = "block";
                this.containerExpandEvent.fire(this);
                YAHOO.log("Container expanded", "info", this.toString());
            }
            else {
                this._elContent.style.display = "none";
                this.containerCollapseEvent.fire(this);
                YAHOO.log("Container collapsed", "info", this.toString());
            }
            this._toggleContainerHelpers(bShow);
            this._bContainerOpen = bShow;
       }

    };

    /**
     * Toggles the highlight on or off for an item in the container, and also cleans
     * up highlighting of any previous item.
     *
     * @method _toggleHighlight
     * @param oNewItem {HTMLElement} The &lt;li&gt; element item to receive highlight behavior.
     * @param sType {String} Type "mouseover" will toggle highlight on, and "mouseout" will toggle highlight off.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._toggleHighlight = function(oNewItem, sType) {
        var sHighlight = this.highlightClassName;
        if(this._oCurItem) {
            // Remove highlight from old item
            YAHOO.util.Dom.removeClass(this._oCurItem, sHighlight);
        }

        if((sType == "to") && sHighlight) {
            // Apply highlight to new item
            YAHOO.util.Dom.addClass(oNewItem, sHighlight);
            this._oCurItem = oNewItem;
        }
    };

    /**
     * Toggles the pre-highlight on or off for an item in the container.
     *
     * @method _togglePrehighlight
     * @param oNewItem {HTMLElement} The &lt;li&gt; element item to receive highlight behavior.
     * @param sType {String} Type "mouseover" will toggle highlight on, and "mouseout" will toggle highlight off.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._togglePrehighlight = function(oNewItem, sType) {
        if(oNewItem == this._oCurItem) {
            return;
        }

        var sPrehighlight = this.prehighlightClassName;
        if((sType == "mouseover") && sPrehighlight) {
            // Apply prehighlight to new item
            YAHOO.util.Dom.addClass(oNewItem, sPrehighlight);
        }
        else {
            // Remove prehighlight from old item
            YAHOO.util.Dom.removeClass(oNewItem, sPrehighlight);
        }
    };

    /**
     * Updates the text input box value with selected query result. If a delimiter
     * has been defined, then the value gets appended with the delimiter.
     *
     * @method _updateValue
     * @param oItem {HTMLElement} The &lt;li&gt; element item with which to update the value.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._updateValue = function(oItem) {
        var elTextbox = this._elTextbox;
        var sDelimChar = (this.delimChar) ? (this.delimChar[0] || this.delimChar) : null;
        var sSavedQuery = this._sSavedQuery;
        var sResultKey = oItem._sResultKey;
        elTextbox.focus();

        // First clear text field
        elTextbox.value = "";
        // Grab data to put into text field
        if(sDelimChar) {
            if(sSavedQuery) {
                elTextbox.value = sSavedQuery;
            }
            elTextbox.value += sResultKey + sDelimChar;
            if(sDelimChar != " ") {
                elTextbox.value += " ";
            }
        }
        else { elTextbox.value = sResultKey; }

        // scroll to bottom of textarea if necessary
        if(elTextbox.type == "textarea") {
            elTextbox.scrollTop = elTextbox.scrollHeight;
        }

        // move cursor to end
        var end = elTextbox.value.length;
        this._selectText(elTextbox,end,end);

        this._oCurItem = oItem;
    };

    /**
     * Selects a result item from the container
     *
     * @method _selectItem
     * @param oItem {HTMLElement} The selected &lt;li&gt; element item.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._selectItem = function(oItem) {
        this._bItemSelected = true;
        this._updateValue(oItem);
        this._cancelIntervalDetection(this);
        this.itemSelectEvent.fire(this, oItem, oItem._oResultData);
        YAHOO.log("Item selected: " + YAHOO.lang.dump(oItem._oResultData), "info", this.toString());
        this._toggleContainer(false);
    };

    /**
     * If an item is highlighted in the container, the right arrow key jumps to the
     * end of the textbox and selects the highlighted item, otherwise the container
     * is closed.
     *
     * @method _jumpSelection
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._jumpSelection = function() {
        if(this._oCurItem) {
            this._selectItem(this._oCurItem);
        }
        else {
            this._toggleContainer(false);
        }
    };

    /**
     * Triggered by up and down arrow keys, changes the current highlighted
     * &lt;li&gt; element item. Scrolls container if necessary.
     *
     * @method _moveSelection
     * @param nKeyCode {Number} Code of key pressed.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._moveSelection = function(nKeyCode) {
        if(this._bContainerOpen) {
            // Determine current item's id number
            var oCurItem = this._oCurItem;
            var nCurItemIndex = -1;

            if(oCurItem) {
                nCurItemIndex = oCurItem._nItemIndex;
            }

            var nNewItemIndex = (nKeyCode == 40) ?
                    (nCurItemIndex + 1) : (nCurItemIndex - 1);

            // Out of bounds
            if(nNewItemIndex < -2 || nNewItemIndex >= this._nDisplayedItems) {
                return;
            }

            if(oCurItem) {
                // Unhighlight current item
                this._toggleHighlight(oCurItem, "from");
                this.itemArrowFromEvent.fire(this, oCurItem);
                YAHOO.log("Item arrowed from", "info", this.toString());
            }
            if(nNewItemIndex == -1) {
               // Go back to query (remove type-ahead string)
                if(this.delimChar && this._sSavedQuery) {
                    if(!this._textMatchesOption()) {
                        this._elTextbox.value = this._sSavedQuery;
                    }
                    else {
                        this._elTextbox.value = this._sSavedQuery + this._sCurQuery;
                    }
                }
                else {
                    this._elTextbox.value = this._sCurQuery;
                }
                this._oCurItem = null;
                return;
            }
            if(nNewItemIndex == -2) {
                // Close container
                this._toggleContainer(false);
                return;
            }

            var oNewItem = this._aListItems[nNewItemIndex];

            // Scroll the container if necessary
            var elContent = this._elContent;
            var scrollOn = ((YAHOO.util.Dom.getStyle(elContent,"overflow") == "auto") ||
                (YAHOO.util.Dom.getStyle(elContent,"overflowY") == "auto"));
            if(scrollOn && (nNewItemIndex > -1) &&
            (nNewItemIndex < this._nDisplayedItems)) {
                // User is keying down
                if(nKeyCode == 40) {
                    // Bottom of selected item is below scroll area...
                    if((oNewItem.offsetTop+oNewItem.offsetHeight) > (elContent.scrollTop + elContent.offsetHeight)) {
                        // Set bottom of scroll area to bottom of selected item
                        elContent.scrollTop = (oNewItem.offsetTop+oNewItem.offsetHeight) - elContent.offsetHeight;
                    }
                    // Bottom of selected item is above scroll area...
                    else if((oNewItem.offsetTop+oNewItem.offsetHeight) < elContent.scrollTop) {
                        // Set top of selected item to top of scroll area
                        elContent.scrollTop = oNewItem.offsetTop;

                    }
                }
                // User is keying up
                else {
                    // Top of selected item is above scroll area
                    if(oNewItem.offsetTop < elContent.scrollTop) {
                        // Set top of scroll area to top of selected item
                        this._elContent.scrollTop = oNewItem.offsetTop;
                    }
                    // Top of selected item is below scroll area
                    else if(oNewItem.offsetTop > (elContent.scrollTop + elContent.offsetHeight)) {
                        // Set bottom of selected item to bottom of scroll area
                        this._elContent.scrollTop = (oNewItem.offsetTop+oNewItem.offsetHeight) - elContent.offsetHeight;
                    }
                }
            }

            this._toggleHighlight(oNewItem, "to");
            this.itemArrowToEvent.fire(this, oNewItem);
            YAHOO.log("Item arrowed to", "info", this.toString());
            if(this.typeAhead) {
                this._updateValue(oNewItem);
            }
        }
    };

    /////////////////////////////////////////////////////////////////////////////
    //
    // Private event handlers
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Handles &lt;li&gt; element mouseover events in the container.
     *
     * @method _onItemMouseover
     * @param v {HTMLEvent} The mouseover event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onItemMouseover = function(v,oSelf) {
        if(oSelf.prehighlightClassName) {
            oSelf._togglePrehighlight(this,"mouseover");
        }
        else {
            oSelf._toggleHighlight(this,"to");
        }

        oSelf.itemMouseOverEvent.fire(oSelf, this);
        YAHOO.log("Item moused over", "info", oSelf.toString());
    };

    /**
     * Handles &lt;li&gt; element mouseout events in the container.
     *
     * @method _onItemMouseout
     * @param v {HTMLEvent} The mouseout event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onItemMouseout = function(v,oSelf) {
        if(oSelf.prehighlightClassName) {
            oSelf._togglePrehighlight(this,"mouseout");
        }
        else {
            oSelf._toggleHighlight(this,"from");
        }

        oSelf.itemMouseOutEvent.fire(oSelf, this);
        YAHOO.log("Item moused out", "info", oSelf.toString());
    };

    /**
     * Handles &lt;li&gt; element click events in the container.
     *
     * @method _onItemMouseclick
     * @param v {HTMLEvent} The click event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onItemMouseclick = function(v,oSelf) {
        // In case item has not been moused over
        oSelf._toggleHighlight(this,"to");
        oSelf._selectItem(this);
    };

    /**
     * Handles container mouseover events.
     *
     * @method _onContainerMouseover
     * @param v {HTMLEvent} The mouseover event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onContainerMouseover = function(v,oSelf) {
        oSelf._bOverContainer = true;
    };

    /**
     * Handles container mouseout events.
     *
     * @method _onContainerMouseout
     * @param v {HTMLEvent} The mouseout event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onContainerMouseout = function(v,oSelf) {
        oSelf._bOverContainer = false;
        // If container is still active
        if(oSelf._oCurItem) {
            oSelf._toggleHighlight(oSelf._oCurItem,"to");
        }
    };

    /**
     * Handles container scroll events.
     *
     * @method _onContainerScroll
     * @param v {HTMLEvent} The scroll event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onContainerScroll = function(v,oSelf) {
        oSelf._elTextbox.focus();
    };

    /**
     * Handles container resize events.
     *
     * @method _onContainerResize
     * @param v {HTMLEvent} The resize event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onContainerResize = function(v,oSelf) {
        oSelf._toggleContainerHelpers(oSelf._bContainerOpen);
    };

    /**
     * Handles textbox keydown events of functional keys, mainly for UI behavior.
     *
     * @method _onTextboxKeyDown
     * @param v {HTMLEvent} The keydown event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onTextboxKeyDown = function(v,oSelf) {
        var nKeyCode = v.keyCode;

        switch (nKeyCode) {
            case 9: // tab
                // select an item or clear out
                if(oSelf._oCurItem) {
                    if(oSelf.delimChar && (oSelf._nKeyCode != nKeyCode)) {
                        if(oSelf._bContainerOpen) {
                            YAHOO.util.Event.stopEvent(v);
                        }
                    }
                    oSelf._selectItem(oSelf._oCurItem);
                }
                else {
                    oSelf._toggleContainer(false);
                }
                break;
            case 13: // enter
                if(!YAHOO.env.ua.webkit) {
                    if(oSelf._oCurItem) {
                        if(oSelf._nKeyCode != nKeyCode) {
                            if(oSelf._bContainerOpen) {
                                YAHOO.util.Event.stopEvent(v);
                            }
                        }
                        oSelf._selectItem(oSelf._oCurItem);
                    }
                    else {
                        oSelf._toggleContainer(false);
                    }
                }
                break;
            case 27: // esc
                oSelf._toggleContainer(false);
                return;
            case 39: // right
                oSelf._jumpSelection();
                break;
            case 38: // up
                YAHOO.util.Event.stopEvent(v);
                oSelf._moveSelection(nKeyCode);
                break;
            case 40: // down
                YAHOO.util.Event.stopEvent(v);
                oSelf._moveSelection(nKeyCode);
                break;
            default:
                break;
        }
    };

    /**
     * Handles textbox keypress events.
     * @method _onTextboxKeyPress
     * @param v {HTMLEvent} The keypress event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onTextboxKeyPress = function(v,oSelf) {
        var nKeyCode = v.keyCode;

            //Expose only to Mac browsers, where stopEvent is ineffective on keydown events (bug 790337)
            if(YAHOO.env.ua.webkit) {
                switch (nKeyCode) {
                case 9: // tab
                    if(oSelf._oCurItem) {
                        if(oSelf.delimChar && (oSelf._nKeyCode != nKeyCode)) {
                            YAHOO.util.Event.stopEvent(v);
                        }
                    }
                    break;
                case 13: // enter
                    if(oSelf._oCurItem) {
                        if(oSelf._nKeyCode != nKeyCode) {
                            if(oSelf._bContainerOpen) {
                                YAHOO.util.Event.stopEvent(v);
                            }
                        }
                        oSelf._selectItem(oSelf._oCurItem);
                    }
                    else {
                        oSelf._toggleContainer(false);
                    }
                    break;
                default:
                    break;
                }
            }

            //TODO: (?) limit only to non-IE, non-Mac-FF for Korean IME support (bug 811948)
            // Korean IME detected
            else if(nKeyCode == 229) {
                oSelf._queryInterval = setInterval(function() { oSelf._onIMEDetected(oSelf); },500);
            }
    };

    /**
     * Handles textbox keyup events that trigger queries.
     *
     * @method _onTextboxKeyUp
     * @param v {HTMLEvent} The keyup event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onTextboxKeyUp = function(v,oSelf) {
        // Check to see if any of the public properties have been updated
        oSelf._initProps();

        var nKeyCode = v.keyCode;

        oSelf._nKeyCode = nKeyCode;
        var sText = this.value; //string in textbox

        // Filter out chars that don't trigger queries
        if(oSelf._isIgnoreKey(nKeyCode) || (sText.toLowerCase() == oSelf._sCurQuery)) {
            return;
        }
        else {
            oSelf._bItemSelected = false;
            YAHOO.util.Dom.removeClass(oSelf._oCurItem,  oSelf.highlightClassName);
            oSelf._oCurItem = null;

            oSelf.textboxKeyEvent.fire(oSelf, nKeyCode);
            YAHOO.log("Textbox keyed", "info", oSelf.toString());
        }

        // Set timeout on the request
        if(oSelf.queryDelay > 0) {
            var nDelayID =
                setTimeout(function(){oSelf._sendQuery(sText);},(oSelf.queryDelay * 1000));

            if(oSelf._nDelayID != -1) {
                clearTimeout(oSelf._nDelayID);
            }

            oSelf._nDelayID = nDelayID;
        }
        else {
            // No delay so send request immediately
            oSelf._sendQuery(sText);
        }
    };

    /**
     * Handles text input box receiving focus.
     *
     * @method _onTextboxFocus
     * @param v {HTMLEvent} The focus event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onTextboxFocus = function (v,oSelf) {
        oSelf._elTextbox.setAttribute("autocomplete","off");
        oSelf._bFocused = true;
        if(!oSelf._bItemSelected) {
            oSelf.textboxFocusEvent.fire(oSelf);
            YAHOO.log("Textbox focused", "info", oSelf.toString());
        }
    };

    /**
     * Handles text input box losing focus.
     *
     * @method _onTextboxBlur
     * @param v {HTMLEvent} The focus event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onTextboxBlur = function (v,oSelf) {
        // Don't treat as a blur if it was a selection via mouse click
        if(!oSelf._bOverContainer || (oSelf._nKeyCode == 9)) {
            // Current query needs to be validated as a selection
            if(!oSelf._bItemSelected) {
                var oMatch = oSelf._textMatchesOption();
                // Container is closed or current query doesn't match any result
                if(!oSelf._bContainerOpen || (oSelf._bContainerOpen && (oMatch === null))) {
                    // Force selection is enabled so clear the current query
                    if(oSelf.forceSelection) {
                        oSelf._clearSelection();
                    }
                    // Treat current query as a valid selection
                    else {
                        oSelf.unmatchedItemSelectEvent.fire(oSelf);
                        YAHOO.log("Unmatched item selected", "info", oSelf.toString());
                    }
                }
                // Container is open and current query matches a result
                else {
                    // Force a selection when textbox is blurred with a match
                    if(oSelf.forceSelection) {
                        oSelf._selectItem(oMatch);
                    }
                }
            }

            if(oSelf._bContainerOpen) {
                oSelf._toggleContainer(false);
            }
            oSelf._cancelIntervalDetection(oSelf);
            oSelf._bFocused = false;
            oSelf.textboxBlurEvent.fire(oSelf);
            YAHOO.log("Textbox blurred", "info", oSelf.toString());
        }
    };

    /**
     * Handles window unload event.
     *
     * @method _onWindowUnload
     * @param v {HTMLEvent} The unload event.
     * @param oSelf {YAHOO.widget.AutoComplete} The AutoComplete instance.
     * @private
     */
    YAHOO.widget.AutoComplete.prototype._onWindowUnload = function(v,oSelf) {
        if(oSelf && oSelf._elTextbox && oSelf.allowBrowserAutocomplete) {
            oSelf._elTextbox.setAttribute("autocomplete","on");
        }
    };

Copyright © 2007 Yahoo! Inc. All rights reserved.