jQuery Detect when browser receives file download | Detecting the File Download Dialog In the Browser

Client Side:

<script src="./../jquery-2.1.4.js"></script>

<script type="text/javascript">
$(document).ready(function () {

var downloadToken = new Date().getTime();

$("button").click(function () {
    downloadToken = new Date().getTime();
    $("[name='downloadToken']").val(downloadToken);
    $("form").trigger("submit");
    timer();
});

function timer() {
    var attempts = 100; /* As you required */
    var downloadTimer = window.setInterval(function () {
        var token = getCookie("downloadToken");
        attempts--;

        if (token == downloadToken || attempts == 0) {
            $(".log").prepend("Browser received file from server<br/>");
            window.clearInterval(downloadTimer);
        }
        else {
            $(".log").prepend("Browser not received file from server yet<br/>");
        }
    }, 1000);
}

function parse(str) {
    var obj = {};
    var pairs = str.split(/ *; */);
    var pair;
    if ('' == pairs[0]) return obj;
    for (var i = 0; i < pairs.length; ++i) {
        pair = pairs[i].split('=');
        obj[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
    }
    return obj;
}

function getCookie(name) {
    var parts = parse(document.cookie);
    return parts[name] === undefined ? null : parts[name];
}

});
</script>

<form action="download.php" method="post">
    <input type="hidden" name="downloadToken"/>
    <button type="button">Download</button>
    <div class="log"></div>
</form>

Server Side Script as of PHP:

<?php
$file_name = "download.zip";
header('Content-Description: File Transfer');
header('Content-Type: application/zip');
header('Content-Disposition: attachment; filename=download.zip');
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file_name));

// Sleep 5 seconds...
sleep(5);

// Cookie will be expire after 20 seconds...
setcookie("downloadToken", $_POST["downloadToken"], time() + 20, "");

ob_clean();
flush();
readfile($file_name);

Browser Screenshot:

Live Example of detect when browser receives file download