beforeunload事件可用于在用户离开页面之前触发操作。由于浏览器限制，此事件用于大量服务器端操作或捕获记录可能不完全可靠
下面是一个使用jQuery向服务器端脚本发出AJAX请求的示例。

$(window).on("beforeunload", function() {
    // Make an AJAX request to capture the record on the server
    $.ajax({
        url: 'capture_record.php',  // Replace with your server-side script
        type: 'POST',
        data: {
            action: 'logout',  // You can send additional data if needed
        },
        async: false,  // Synchronous request to give it time to execute before leaving
    });
    
    // Your confirmation message (some browsers may not show this message)
    return "Do you really want to close?";
});

<?php
// capture_record.php

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if ($_POST['action'] === 'logout') {
        // Capture the record in the database or perform other actions
        // Example: Insert a logout record into a database
        // $userId = $_SESSION['user_id'];
        // $timestamp = time();
        // Write a Query for DB Record with parameter ($userId, $timestamp);

        // Respond to the AJAX request
        echo 'Record captured successfully';
        exit;
    }
}

// Handle other actions or respond accordingly
?>

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