Prevent double-clicking from submitting forms multiple times

Some users double-click form buttons rather than single
clicking as expected and on some forms in some browsers,
this can cause double updates. For example, double clicking
on a ticket comment/reply can post the response twice.

Other forms such as searches might just run the search
twice, using extra server resources needlessly.

Allow all forms to be submitted only once by adding a
CSS class as a flag to indicate the form has been
submitted.

share/static/js/util.js

@@ -1005,6 +1005,22 @@ jQuery(function() {
         );
         return false;
     });
+
+    // Submit all forms only once.
+    // This stops all forms of double-clicking or double
+    // enter/return key.
+    jQuery('form').each(function() {
+        var form = jQuery(this);
+        form.on('submit', function (e) {
+            // Prevent if already submitting
+            if (form.hasClass('rt-form-submitted')) {
+                e.preventDefault();
+            }
+
+            // Add class to hook our visual indicator on
+            form.addClass('rt-form-submitted');
+        });
+    });
 });
 
 function filterSearchResults () {