Check numeric validation in jQuery

<script type="text/javascript">

     var specialKeys = new Array();

     specialKeys.push(8); //Backspace

     function IsNumeric(e) {

         var keyCode = e.which ? e.which : e.keyCode

         var ret = ((keyCode >= 48 && keyCode <= 57) || specialKeys.indexOf(keyCode) != -1);

         return ret;

     }

    </script>