//檢查 E-Mail 欄位是否空白與格式

String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ""); };

function ckh_mail(obj){
	if (!obj.email.value.trim()){
		alert('電子郵件不得為空白');
		obj.email.focus();
		return false;
	}
	if (!CheckMail(obj.email)){
		alert('電子郵件格式錯誤');
		obj.email.focus();
		return false;
	}
	return true;
}

function CheckMail(objMail) {
  var email = objMail.value.trim();
  var rege = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9])+$/;
  if (email.length == 0 || rege.exec(email) == null) {
    return false;
  }
  return true;
}