function isEmail(mail){
    var er = new RegExp(/^[A-Za-z0-9_\-\.]+@[A-Za-z0-9_\-\.]{2,}\.[A-Za-z0-9]{2,}(\.[A-Za-z0-9])?/);
    
	if(er.test(mail)){
		return true; 
	}else{return false;}
}