How to use PHP control to close the current web page

When we develop a website, we often have to implement some special functions. Among them, one common requirement is to control users to close browser tabs or close the entire browser window. This purpose can be achieved through PHP language. In this article, we will introduce how to implement this functionality in PHP.

1. Use JavaScript to realize the function of blocking and closing web pages

Before I start to introduce how to use PHP language to block and close the function of web pages, let me first introduce how to use JavaScript to realize the function of blocking and closing web pages.

In JavaScript, we can use the onbeforeunload event to perform related operations. This event is fired before closing the browser tab or browser window. We can write code to operate when the event is triggered to achieve the effect of shielding and closing.

Below, we demonstrate a piece of JavaScript code to block and close the current web page:

window.onbeforeunload = function () {
    return "确定要离开当前页面吗？";
};

In this code, we use the onbeforeunload event, and the content in the function is the prompt information. When the browser attempts to close the current tab or the entire window, the system will pop up a confirmation box displaying the above text content. If the user selects OK, the page will be closed, otherwise it will remain on the current page.

Of course, JavaScript can only modify the front-end page behavior. For server-side PHP, it has many other things to do. In this article, we will introduce how to implement the function of closing a web page in PHP.

2. Use PHP to implement the function of blocking and closing web pages

To implement the function of blocking and closing web pages in PHP, we need to use the session mechanism to achieve it. The session mechanism is a session mechanism based on the HTTP protocol, which is used to save data between the client and the server. In the session, we can store some information, which can be easily obtained during the next request.

The following is the code that uses PHP to block and close the web page:

session_start();
$_SESSION['showMessage'] = true;

In this code, we use the session_start() function to open the session, and use the $_SESSION array to save some variables across pages . Here, we set $_SESSION['showMessage'] to true, indicating that a confirmation box needs to pop up on the next page.

Next, on the next page, we need to take out the value of $_SESSION['showMessage'] and determine whether it is necessary to pop up the confirmation box. The specific code is as follows:

session_start();
if (isset($_SESSION['showMessage']) && $_SESSION['showMessage'] === true) {
    echo '<script>alert("确定要离开当前页面吗？");</script>';
    unset($_SESSION['showMessage']);
}

In this code, we use the isset() function to determine whether $_SESSION['showMessage'] exists, and at the same time determine whether its value is true. If so, use echo to output the JavaScript code and pop up a confirmation box. After the confirmation box pops up, we also need to set the value of $_SESSION['showMessage'] to null to avoid multiple confirmation boxes popping up.

3. Comprehensive use of JavaScript and PHP to implement the function of blocking and closing web pages

In actual development, due to the complicated jump relationship between pages, we cannot guarantee that users will Jump to next page. Therefore, we need to make judgments in both the front-end (JavaScript) and the back-end (PHP).

The following is the code that uses JavaScript and PHP to block and close the web page:

JavaScript code:

window.onbeforeunload = function () {
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.open("GET", "close.php", false);
    xmlhttp.send();
    return "确定要离开当前页面吗？";
};

PHP code:

session_start();
if (isset($_REQUEST['close'])) {
    $_SESSION['showMessage'] = false;
    exit;
}
if (isset($_SESSION['showMessage']) && $_SESSION['showMessage'] === true) {
    echo '<script>alert("确定要离开当前页面吗？");</script>';
    unset($_SESSION['showMessage']);
}

In this code , we use the XMLHttpRequest object to trigger the Ajax request and submit it to the background PHP file to achieve the effect of executing background PHP in the front-end JavaScript. The PHP file will set the value of $_SESSION['showMessage'] to false, and on the next page, the code that pops up the confirmation box will no longer be executed.

Conclusion

In this article, we introduced how to use PHP language to block the function of closing the web page. By using the session mechanism, we can maintain an intermediate variable on the server side to determine whether a confirmation box needs to pop up.

This article also introduces how to use JavaScript and PHP to implement the function of blocking and closing web pages. By using both front-end (JavaScript) and back-end (PHP) to make judgments, we can better ensure the reliability of the function of blocking and closing web pages.

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