function checkEmail(email){
	var proto  = "(mailto:)?";
  	var usr    = "([a-zA-Z0-9][a-zA-Z0-9_.-]*|\"([^\\\\\x80-\xff\015\012\"]|\\\\[^\x80-\xff])+\")";
  	var domain = "([a-zA-Z0-9][a-zA-Z0-9._-]*\\.)*[a-zA-Z0-9][a-zA-Z0-9._-]*\\.[a-zA-Z]{2,5}";
  	var regex  = "^" + proto + "?" + usr + "\@" + domain + "$";

	var rgx    = new RegExp(regex);
  	var erg = rgx.exec(email);

  	if(erg && email != ""){
  		return true;
 	}
	else{
		//alert("Ungültige E-Mail Adresse angegeben.");
		return false;
	}
}