How do I use the onclick on a checkbox?

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Javascript

HTML

PHP

I have this:
<input type="checkbox" onclick="windows.location.href='admin-dashboard.php?action=approveapp&id=

<?php echo $row['app_id']; ?>

'">

And this:

if (isset($_GET["id"]))
{
    $id = $_GET["id"];
    echo "ID: ".$id;
    if (isset($_GET["action"]))
    {
        $action = $_GET["action"];
        echo "ACTION: ".$action;
        switch ($action)
        {
            case "approveapp":
                $sql = "UPDATE tblapplications SET approved = 1 WHERE app_id = $id";
                echo $sql;
                mysqli_query($conn, $sql);
                break;
        }
    }
    else {
        $action = "";
    }
}
else {
    $id = "";
}

When the checkbox is clicked, it's supposed to perform some query to the database, but when I click on the checkbox, nothing happens. Am I missing something?