diff --git a/misc/tabledrag.js b/misc/tabledrag.js
index 9916821..07a57ac 100644
--- a/misc/tabledrag.js
+++ b/misc/tabledrag.js
@@ -1014,7 +1014,7 @@
   var siblings = new Array();
   var directions = new Array('prev', 'next');
    var rowIndentation = this.indents;
-  for (var d in directions) {
+  for (var d=0; d < directions.length; d++) {
     var checkRow = $(this.element)[directions[d]]();
     while (checkRow.length) {
       // Check that the sibling contains a similar target field.