remove GET parameter in URL after processing is finished(not using POST), PHP

Put this in your HTML file (HTML5).

<script>    
    if(typeof window.history.pushState == 'function') {
        window.history.pushState({}, "Hide", "http://localhost/join/prog/ex.php");
    }
</script>

Or using a backend solution using a session for instance;

<?php
    session_start();

    if (!empty($_GET)) {
        $_SESSION['got'] = $_GET;
        header('Location: http://localhost/join/prog/ex.php');
        die;
    } else{
        if (!empty($_SESSION['got'])) {
            $_GET = $_SESSION['got'];
            unset($_SESSION['got']);
        }

        //use the $_GET vars here..
    }

SIMPLE ANSWER

Just place this in the top of the file you need to make the GET querys disappear from the browser's URL bar after loading.

<script>    
    if(typeof window.history.pushState == 'function') {
        window.history.pushState({}, "Hide", '<?php echo $_SERVER['PHP_SELF'];?>');
    }
</script>