php 判断是否邮箱

<?php
function is_valid_email($email) {
    // 正则表达式用于验证邮箱格式
    $pattern = '/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/';
    return preg_match($pattern, $email);
}

// 测试
$email = "example@example.com";
if (is_valid_email($email)) {
    echo "邮箱地址有效";
} else {
    echo "邮箱地址无效";
}
?>

<?php
$email = "example+123@example.com";
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "邮箱地址有效";
} else {
    echo "邮箱地址无效";
}
?>

<?php
function check_email_domain($email) {
    $domain = substr(strrchr($email, "@"), 1);
    if (checkdnsrr($domain, "MX")) {
        return true;
    } else {
        return false;
    }
}

$email = "example@example.com";
if (is_valid_email($email) && check_email_domain($email)) {
    echo "邮箱地址有效且域名存在";
} else {
    echo "邮箱地址无效或域名不存在";
}
?>