function checkmail(mail){
	var btloc=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i  ;
	if(btloc.test(mail)) 
	   return true ;
	else { 
	   alert("Email-Adres isn't correct!"); 
	   return false; 
	} 
}