メールアドレスの正規表現

script.js

console.log(valid_mail_address2('[email protected]'));
console.log(valid_mail_address2('[email protected]'));
console.log(valid_mail_address2('hogehoge.fugafuga.com'));
console.log(valid_mail_address2('hogehoge@fugafuga@com'));
console.log(valid_mail_address2('@fugafuga.com'));
console.log(valid_mail_address2('hogehoge@fugafuga'));
console.log(valid_mail_address2('[email protected]'));

function valid_mail_address2(mail) {
  //正規表現
	var reg = /^[A-Za-z0-9]{1}[A-Za-z0-9_.-]*@{1}[A-Za-z0-9_.-]{1,}\.[A-Za-z0-9]{1,}$/;
	return reg.test(mail);
}


function valid_mail_address(mail) {
	var split_mail = mail.split('@');
	if (split_mail.length !== 2) {
		return false;
	}

	if (split_mail[0].length === 0) {
		return false;
	}

	var split_mail2 = split_mail[1].split('.');
	if (split_mail2.length <= 1) {
		return false;
	}

	for (var i = 0; i < split_mail2.length; i++) {
		if (split_mail2[i].length === 0) {
			return false;
		}
	}

	return true;
}