function allowNumbers(field, event)
{
	//alert(event.keyCode);
  var keyCode = event.keyCode ? event.keyCode : 
                event.which ? event.which : event.charCode;
  if ((keyCode > 47 && keyCode < 58) || (keyCode > 95 && keyCode < 106) || (keyCode==8) || (keyCode==13))
    return true;

  return false;
}