TimeoutAndRedirect 未在 onload() 中定义

如何解决TimeoutAndRedirect 未在 onload() 中定义

我正在尝试通过 AJAX 登录，但看起来我不能这样做......基本上，我想要做的是，根据用户类型，登录后，我应该被重定向到某个页面。调用如下所示：<body onload="TimeoutAndRedirect('student')">
有时我可以登录，有时我不能，我不明白为什么...这是我的 timeoutandredirect 函数，我最初使用了 cookie 和 XHR 请求，但它太慢了：

function TimeoutAndRedirect(Type) {
     $.ajax
    ({
  type: "GET",url: "../PHP/redirect.PHP",success: function(respond)
  {

            if (respond == "not logged.") {
                alert("Your login period has expired! Please login again!");
                window.location.href = "../login.html";
            } 
            else if (respond != Type) {
            alert("You cannot access this page using your account!");
             if (respond == "admin") {
                 window.location.href = "../page/admin-system-management.PHP";
             } else if (respond == "student"){
                 window.location.href = "../page/student-dashboard.PHP";
             } else if (respond == "teacher"){
                 window.location.href = "../page/teacher-dashboard.PHP";
             }
         }
        }
    }
    // var Request = new XMLHttpRequest();
    // Request.open("GET","../PHP/redirect.PHP",true);
    // Request.send();
    // Request.onload = function() {
     //     var respond = Request.responseText;
     //     if (respond == "not logged.") {
     //         alert("Your login period has expired! Please login again!");
     //         window.location.href = "../login.html";
     //     } else if (respond != Type) {
     //        alert("You cannot access this page using your account!");
     //         if (respond == "admin") {
     //             window.location.href = "../page/admin-system-management.PHP";
     //         } else if (respond == "student"){
     //             window.location.href = "../page/student-dashboard.PHP";
     //         } else if (respond == "teacher"){
     //             window.location.href = "../page/teacher-dashboard.PHP";
     //         }
     //     }
     // }
}

这是我的 checklogin.js 文件：

function login() {
    var enterID = document.getElementById("enterID").value;
    var password = document.getElementById("password").value;
 if ((password != "") && (enterID != "")) {

 var info = "?enterID=" + enterID + "&password=" + password;
 
 $.ajax
({
  type: "GET",url: "PHP/login.PHP"+info,success: function(respond)
  {
  
            if (respond == "admin") {
                window.location.href = "page/admin-system-management.PHP";
            } else if (respond == "student"){
                window.location.href = "page/student-dashboard.PHP";
            } else if (respond == "teacher"){
                window.location.href = "page/teacher-dashboard.PHP";
            } else{
                document.getElementById("errorMessage").innerText = respond;
            }  
  
 
  }
});
}
     else {
        document.getElementById("errorMessage").innerText = "Please fill in all the fields.";
    }
}

function redirect() {

 $.ajax
({
  type: "GET",url: "PHP/redirect.PHP",success: function(respond)
  {
  
                 if (respond != "not logged.") {
            if (respond == "admin") {
                window.location.href = "page/admin-system-management.PHP";
            } else if (respond == "student"){
                window.location.href = "page/student-dashboard.PHP";
            } else if (respond == "teacher"){
                window.location.href = "page/teacher-dashboard.PHP";
            }
        }
  
 
  }
});
}

这是我的 login.PHP 文件：

<?PHP
session_start();
        include "mysql-connect.PHP";
        
        //get Info from login.html
        $ID = $_GET['enterID'];
        $PW = $_GET['password'];
        $stmt = $connect->prepare("SELECT PW,userType,nickName FROM users WHERE ID = ?");
        $stmt->bind_param("s",$ID);
        $valid = $stmt->execute();
        if (!$valid){
            die("Could not successfully run query.". $connect->connect_error);
        }
        $result = $stmt->get_result();
        if ($result->num_rows==0){
            //display message of no such student/teacher/admin
            echo "Failed to find an account with the input ID.";
        } else {
            $row = $result->fetch_assoc();
            if ($PW == $row['PW']) {
                $type = $row['userType'];
                $nick = $row['nickName'];
                //save data,record cookie for 6hours
                $_SESSION["type"]=$type;
                $_SESSION["userID"]=$ID;
                $_SESSION["nickName"]=$nick;
                //login success - Request.responseText to checklogin.js
                echo $type;

            } else {
                //display message of password error
                echo "The input password does not match the account password.";
            }
        }
        $connect->close();
?>

我做错了什么？有时我也遇到了，，XHR加载GET失败”，然后我断开连接，然后我再次尝试登录，我需要再等几秒钟才能尝试登录，我不明白为什么..