function objekt(what) {return document.getElementById(what);}

function isEmpty(e) {
  return ((e == null) || (e.length == 0));
}

function isEmail(mail) {
  re = /^[_a-zA-Z0-9\.\-]+@[_a-zA-Z0-9\.\-]+\.[a-zA-Z]{2,7}$/;
  return mail.search(re) == 0;
}