Added back check in JS for empty or default URL.

common/lib/xmodule/xmodule/js/src/lti/lti.js

@@ -37,7 +37,7 @@ window.LTI = (function () {
     //
     // @return    undefined
     function initialize(element) {
-        var form, openInANewPage;
+        var form, openInANewPage, formAction;
 
         // In cms (Studio) the element is already a jQuery object. In lms it is
         // a DOM object.
@@ -47,6 +47,16 @@ window.LTI = (function () {
         element = $(element);
 
         form = element.find('.ltiLaunchForm');
+        formAction = form.attr('action');
+
+        // If action is empty string, or action is the default URL that should
+        // not cause a form submit.
+        if (!formAction || formAction === 'http://www.example.com') {
+
+            // Nothing to do - no valid action provided. Error message will be
+            // displaced in browser (HTML).
+            return;
+        }
 
         // We want a Boolean 'true' or 'false'. First we will retrieve the data
         // attribute, and then we will parse it via native JSON.parse().