var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;

function AllowNumbers(e) {
  var key; 
  var keychar; 
  var re = /[\d\x08\x0D\-.]/;
  if (window.event) {
    key = e.keyCode;
  } else if (e.which) {
    key = e.which;
  } else {
    return true;
  }
  keychar = String.fromCharCode(key);
  return re.test(keychar);
}