function emailCheck(obj) {
  var adress = /^([^\s@,:"<>]+)@([^\s@,:"<>]+\.[^\s@,:"<>.\d]{2,}|(\d{1,3}\.){3}\d{1,3})$/;
  var result = obj.value.match(adress);
  var check = true;
  if (!result) {
     alert("Geben Sie eine gültige E-Mail-Adresse ein!");
	 obj.select();
     return false;
  }
}

function emptyField(obj) {
  var eMail = obj.value;
  if (eMail == "Ihre E-Mail-Adresse") {
     obj.value = "";
  }
}