Restore jquery.frameready.js code from 1.11.x - refs BT#21508

public/main/inc/lib/javascript/jquery.frameready.js

@@ -17,7 +17,7 @@
         factory(jQuery);
     }
 }(function ($) {
-    $.frameReady = function (callback, targetSelector, resources) {
+    $.frameReady = function (callback, targetSelector, resources, conditional) {
         /**
          * @type {window}
          */
@@ -59,8 +59,17 @@
         targetWindow.onload = function () {
             scripsLoadedCount = 0;
 
+            if (typeof conditional === 'function' && conditional()) {
+                return;
+            }
+
             targetDocument = targetWindow.contentDocument;
 
+            if (!targetDocument) {
+                console.log('frameReady: Can\'t access to contentDocument.');
+                return;
+            }
+
             scripts.forEach(function (script) {
                 createScript(script);
             });