function isNumberKey(evt)
      {
         var charCode = (evt.which) ? evt.which : event.keyCode
         if (charCode == 8 || charCode == 13 || charCode >= 48 && charCode <= 57)
	  {
		return true;
	  }

         return false;
      }


// 8 = backspace
// 13= return
// 48-57 = numbers