在我的表单上，我允许用户将文件上传到数据库，然后我将它们发送到另一个页面，即 submission_successful.php，上面写着“感谢您提交”。但我注意到，当我点击提交成功的 php 文件上的后退按钮时，它会返回到表单并且那里有相同的信息并允许再次提交。我想要做的是在点击后退按钮时终止代码，或者清除用户输入的所有内容。我找到了几个答案，比如使用 缓存控制，但是有些含糊不清，有些对我不起作用。另外，我不希望用户在成功页面上时返回到上传页面。所以这就是为什么我会为“注销”或“返回上传页面”创建 2 个按钮，如果它们点击返回按钮，它将崩溃。我想显示 Confirm Form Resubmission页。在其他帖子中，他们试图真正阻止“确认表格重新提交”，但为了安全起见，我想拥有它。这是我的代码

developerUpload.php

<?php

session_start();

if(array_key_exists("invalid", $_GET)){

    echo '<br><h3 style="color:red;">File(s) were already submitted! Please re-name file or select a different file...</h3>';
}

if(isset($_COOKIE['username'])){

    if($_SERVER['REQUEST_METHOD'] =="POST"){

        $price = addslashes(trim($_POST['price']));
        $description = addslashes(trim($_POST['description']));

        if(!empty($price) && !empty($description)){

            $userid = $_SESSION['id'];
            $username = $_SESSION['username'];
            echo '<br>'.$userid;
            $pack_id = rand();

            //Check file 1
            if($_FILES['file1']['error'] !== UPLOAD_ERR_OK){

                    $file1 = null;
            }else{

                $target1 = "devFiles/";
                $target_file1 = addslashes(trim($target1 . basename($_FILES["file1"]["name"])));
                $file1 = addslashes(trim($_FILES['file1']['tmp_name']));

            }

            //Check file 2
            if($_FILES['file2']['error'] !== UPLOAD_ERR_OK){

                    $file2 = null;
            }else{

                $target2 = "devFiles/";
                $target_file2 = addslashes(trim($target2 . basename($_FILES["file2"]["name"])));
                $file2 = addslashes(trim($_FILES['file2']['tmp_name']));

            }

            //Check file 3
            if($_FILES['file3']['error'] !== UPLOAD_ERR_OK){

                    $file3 = null;
            }else{

                $target3 = "devFiles/";
                $target_file3 = addslashes(trim($target3 . basename($_FILES["file3"]["name"])));
                $file3 = addslashes(trim($_FILES['file3']['tmp_name']));

            }

            //Check file 4
            if($_FILES['file4']['error'] !== UPLOAD_ERR_OK){

                    $file4 = null;
            }else{

                $target4 = "devFiles/";
                $target_file4 = addslashes(trim($target4 . basename($_FILES["file4"]["name"])));
                $file4 = addslashes(trim($_FILES['file4']['tmp_name']));

            }

            //Check file 5
            if($_FILES['file5']['error'] !== UPLOAD_ERR_OK){

                    $file5 = null;
            }else{

                $target5 = "devFiles/";
                $target_file5 = addslashes(trim($target5 . basename($_FILES["file5"]["name"])));
                $file5 = addslashes(trim($_FILES['file5']['tmp_name']));

            }

            //Check video
            if($_FILES['video']['error'] !== UPLOAD_ERR_OK){

                $video = null;
                $videoName = null;
            }else{

                $target = "devFiles/";
                $target_file = addslashes(trim($target . basename($_FILES["video"]["name"])));
                $video = addslashes(trim($_FILES['video']['tmp_name']));
                $videoName = addslashes(trim($_FILES['video']['name']));

            }

            if(file_exists($target_file1) 
               or file_exists($target_file2) 
               or file_exists($target_file3)
               or file_exists($target_file4) 
               or file_exists($target_file5) 
               or file_exists($target_file)){

                header("Location: developerUpload.php?invalid");
                exit;

            }

            if(move_uploaded_file($_FILES["file1"]["tmp_name"], $target_file1) 
               && move_uploaded_file($_FILES["file2"]["tmp_name"], $target_file2)
               && move_uploaded_file($_FILES["file3"]["tmp_name"], $target_file3)
               && move_uploaded_file($_FILES["file4"]["tmp_name"], $target_file4)
               && move_uploaded_file($_FILES["file5"]["tmp_name"], $target_file5)
               && move_uploaded_file($_FILES["video"]["tmp_name"], $target_file)){

                try{

                    // new php data object 
                    $handler = new PDO('mysql:host=127.0.0.1;dbname=magicsever', 'root', '');
                    //ATTR_ERRMODE set to exception
                    $handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

                }catch(PDOException $e){
                    die("There was an error connecting to the database");   

                }

                header("Location: submission_successful.php?");
                die();
            }



        }else{

            echo '<br><h1 style="color:red;">VALUES MISSING!</h1>';

        }
    }
}else {

    header("Location: developerLogin.php");
}



?>

提交成功.php

<?php
session_start();

    if(array_key_exists("invalid", $_GET)){

        header("Location: developerUpload.php?invalid");

    }
    if(isset($_COOKIE['username'])){
        echo '<br><h1 style="color:red; text_align:center;">Thank You for Submitting!</h1>';

    }else{

        header("Location: developerLogin.php");
    }

?>

最佳答案

我找了好几天，终于找到了一些东西。如果您使用 HTML 命令，它会在用户返回时删除用户输入的任何内容。因为我的问题是当用户在被重定向后返回时，他们的信息仍然存在但是如果你使用

<form method="post" enctype="multipart/form-data" autocomplete="off">

它删除了所有内容，所以有点帮助。用户仍将被允许返回，但至少现在他们不能重新提交数据。

关于php - 刷新页面或单击后退按钮时如何防止重新提交表单，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44991941/