PHP验证邮件地址

function is_valid_email($email, $test_mx = false)
{
    if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})[    wind_phpcode_0    ]quot;, $email))
        if($test_mx)
        {
            list($username, $domain) = split("@", $email);
            return getmxrr($domain, $mxrecords);
        }
        else
            return true;
    else
        return false;
}