我自己寫了一個方法 如下 

$_SERVER['HTTP_REFERER']

 可以檢視上個頁面傳遞過來的引數

<?php
header('content-type:text/html;charset=utf-8');
include_once './lib/fun.php';
judgeVx();
if (checkLogin()) {
    msg(1, '您已登入', 'index.php');
}
//表單進行了提交處理
$gourl = 'index.php';
if (empty($_POST['username']) && strstr($_SERVER['HTTP_REFERER'], $_SERVER['HTTP_HOST'])) {
    $gourl = str_replace(getProtocol() . $_SERVER['HTTP_HOST'], "", $_SERVER['HTTP_REFERER']);
}

if (!empty($_POST['username']) && !empty($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    $res = login($username, $password);

    if ($res == "登入成功") {
//        如果傳遞過來的域名 包含我們的域名 那麼就替換掉 並且跳轉
        header("Location:" . $_POST['gourl']);
    } else {
        msg(2, $res);

    }
}
?>
 

在登入的表單上多提交一個引數

 <input type="hidden" name="gourl" value="<?php echo $gourl ?>">
            <button style="submit" class="login_btn">登 錄</button>

function getProtocol()
{
    //主動判斷是否HTTPS
    if (is_https()) {
        return "https://";
    } else {
        return "http://";
    }
}
 

function is_https()
{
    if (!empty($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) !== 'off') {
        return true;
    } elseif (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
        return true;
    } elseif (!empty($_SERVER['HTTP_FRONT_END_HTTPS']) && strtolower($_SERVER['HTTP_FRONT_END_HTTPS']) !== 'off') {
        return true;
    }
    return false;
}