I have a column of input fields that I validate for numbers only. If it's a NaN I want to display a message and refocus when the user tries to click away.

The following code will fail in IE9 to refocus back to the offending value. But I had to insert (by pure accident) an extra random focus line to force it to focus correctly. Any ideas? 

2. <input type='text' class='unit' value=""/>
3. 
   
4. $("input[class=unit]").change(function(){
5. if ( !isInt($(this).val()) || Number($(this).val())<0 ) {
6. alert("Not an integer  "+$(this).val());
7. var oldUnits=$(this).data('oldUnits');
8. $(this).val(oldUnits);
9. 
   
10. $('#unit1').focus(); // fix for IE9 not focusing
12. $(this).focus();
13. return false;
14. }
15. });