"tabindex" selector: IE6 Vs FF3.6

"tabindex" selector: IE6 Vs FF3.6

Currently our company is migrating from IE6 to FireFox 3.6. For some time both browser will be used in parallel.
The selector $("[tabindex]") seems to act differently on both browsers, consider the following code:

  1. <script type="text/javascript">
  2. $(document).ready(function() {
  3.     var output = "";
  4.     $("[tabindex]").each(function(i, elem) {
  5.             output += "<br/>";
  6.             output += $(elem).attr("text") + ":" +  $(elem).attr("tabindex");
  7.     });
  8.     $("#result").html(output);
  9. });
  10. </script>
  11. <form>
  12.     Text <input tabindex="1" text="Text" type="text">
  13.     Check <input tabindex="2" text="Check" type="checkbox">
  14.     <input tabindex="3" text="Login" type="button" value="Login">
  15.     <br/>
  16.     _Text <input text="_Text" type="text">
  17.     _Check <input text="_Check" type="checkbox">
  18.     <input text="_Login" type="button" value="Login">
  19.     <p id="result">
  20. </form>

The result on FireFox is, as espected, a list of element text and tabindex: 
 Text:1 Check:2 Login:3
On IE6, the selector seems to take all elements, and the result is: 
 undefined:undefined undefined:undefined :undefined :undefined :undefined $(document).ready(function() { var output = ""; $("[tabindex]").each(function(i, elem) { output += " "; output += $(elem).attr("text") + ":" + $(elem).attr("tabindex"); }); $("#result").html(output); }); :undefined undefined:0 Text:1 Check:2 Login:3 undefined:undefined _Text:0 _Check:0 _Login:0 undefined:undefined
Any idea how can I select in IE6 only elements with a defined tabindex attribute ?