MDL-28406 blocks: added JS to prevent the addition of duplicate blocks

lib/javascript-static.js

@@ -352,21 +352,29 @@ M.util.init_select_autosubmit = function(Y, formid, selectid, nothing) {
             // Make sure we have the form
             if (form) {
                 // Create a function to handle our change event
-                var processchange = function(e, lastindex) {
-                    if ((nothing===false || select.get('value') != nothing) && lastindex != select.get('selectedIndex')) {
+                var processchange = function(e, paramobject) {
+                    if ((nothing===false || select.get('value') != nothing) && paramobject.lastindex != select.get('selectedIndex')) {
+                        //prevent event bubbling and detach handlers to prevent multiple submissions caused by double clicking
+                        e.halt();
+                        paramobject.eventkeypress.detach();
+                        paramobject.eventblur.detach();
+                        paramobject.eventchangeorblur.detach();
+
                         this.submit();
                     }
                 };
                 // Attach the change event to the keypress, blur, and click actions.
                 // We don't use the change event because IE fires it on every arrow up/down
                 // event.... usability
-                Y.on('key', processchange, select, 'press:13', form, select.get('selectedIndex'));
-                select.on('blur', processchange, form, select.get('selectedIndex'));
+                var paramobject = new Object();
+                paramobject.lastindex = select.get('selectedIndex');
+                paramobject.eventkeypress = Y.on('key', processchange, select, 'press:13', form, paramobject);
+                paramobject.eventblur = select.on('blur', processchange, form, paramobject);
                 //little hack for chrome that need onChange event instead of onClick - see MDL-23224
                 if (Y.UA.webkit) {
-                    select.on('change', processchange, form, select.get('selectedIndex'));
+                    paramobject.eventchangeorblur = select.on('change', processchange, form, paramobject);
                 } else {
-                    select.on('click', processchange, form, select.get('selectedIndex'));
+                    paramobject.eventchangeorblur = select.on('click', processchange, form, paramobject);
                 }
             }
         }