编写一个验证电子邮件的格式是否正确的函数

function checkEmail($email)
{
    $pregEmail = "/([a-z0-9]*[-_\.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[a-z0-9]+)+[\.][a-z]{2,3}([\.][a-z]{2})?/i";
    return preg_match($pregEmail,$email);
}