MT#5879 Prevent add back link again and again on applying onload method after ajax tables reload

share/layout/body.tt

@@ -157,7 +157,7 @@ var mainWrapperInit = function () {
         }
         var _href = $(this).attr('href');
         var _back = 'back=[% backuri | uri %]';
-        if(_href == null) {
+        if(_href == null || _href.match(/[&\?]back=/)) {
             // ignore 
         } else if(_href.match(/\?/)) {
             $(this).attr('href', _href + '&' + _back);