Use some JS to prevent people clicking the submit button twice on the ITransact checkout screen. Fixes bug #11351

docs/changelog/7.x.x.txt

@@ -7,6 +7,7 @@
  - fixed #11344: Badge Builder doesn't allow pagination
  - fixed #11348: Typ-o in debug notice SQLReport
  - fixed #11350: Story Topic asset missing description...
+ - fixed #11351: Double submits on ITransact checkout
 
 7.8.9
  - fixed #11235: wiki search

lib/WebGUI/Shop/PayDriver/ITransact.pm

@@ -809,6 +809,7 @@ sub www_getCredentials {
 
     $var->{checkoutButton} = WebGUI::Form::submit($session, {
         value => $i18n->get('checkout button', 'Shop'),
+        extras => 'onclick="this.disabled=true;"',
     });
 
     my $template = WebGUI::Asset::Template->new($session, $self->get("credentialsTemplateId"));