MT#4903 Fix javascript error on empty referrer

let it match a controller that does not exists
(This broke in (MT#4287))
and exclude get parameters from that match

share/templates/helpers/datatables.tt

@@ -25,7 +25,7 @@ $.extend( $.fn.dataTableExt.oStdClasses, {
             } );
 
 $(document).ready(function() {
-    var prev_controller = document.referrer.match(/:\/\/[^/]*\/([^/]+)/).pop();
+    var prev_controller = (document.referrer || "http://is.invalid/invalid_controller").match(/:\/\/[^/]*\/([^/?]+)/).pop();
     var this_controller = window.location.pathname.match(/[^/]+/g)[0];
     if (prev_controller != this_controller) {
         localStorage.removeItem('ngcp_dt_[% helper.id_from_name %]_table');