如何使用AJAX向$ _SESSION赋值？

Question

Yes, I'm aware that this question has already been post, but ... I'm looking for a way to check if the Client has Javascript Enabled.

Here is my idea : At every loading page, PHP initialize $_SESSION['is_js'] to 0 . Then, I wish AJAX to ( via launching a script php ? ) try to set $_SESSION['is_js'] to 1 . If JS is enabled, AJAX will succeed, if not, the value remains 0.

I can't use jQuery or others libraries... I have to write this in pure AJAX ( I mean not using framework or librairies ), and I have no idea how to do this.

Edit : I can't use cookie. I don't want to use <noscript> .

Answer 1

First you need to learn to do a ajax call in pure javascript, some website like w3schools or others

And in the php files that the ajax call , you can set the session variable to 1.

But there's maybe better way to find if the client have javascript enable.

EDIT: I suggest to check if your session variable is , if not, try the ajax call and set the variable at 0 . If at page loading the variable is set and equal, that means the client doesn't have javascript/xmlhttprequest enable.

And for a session, a cookie is store on the client side. So if the client refuse to store any cookie, you will never haver information in your session variables.

Answer 2

I would use a cookie. It will function nearly identical --

<?php
$_SESSION['js'] = (int) $_COOKIE['js']
setcookie('js', 0);
?>
<script type="text/javascript">
setCookie('js', 1);
</script>

You can use a set of cookie functions such as http://www.w3schools.com/js/js_cookies.asp

Good luck!

Answer 3

A rather unique (and IMO lame) approach is to use javascript to download a fake image:

<script type="text/javascript">
var fake = new Image();
fake.src = "/sess_js.php";
</script>

Doesn't use AJAX, jQuery, Cookies, etc.

Answer 4

According to your idea and your requirements, if you can't use a library like jQuery or Prototype, and so on... you are enforced to use the "raw" XMLHttpRequest Object . The following code is an example.

Create a file called ajax_js_enabled_test.php and put this code inside:

<?php

    if(isset($_GET['PHPSESSID'])) session_id($_GET['PHPSESSID']);
    session_start();

    if(isset($_SESSION['user_js_support']) && $_SESSION['user_js_support']) echo "Javascript enabled";
    else $_SESSION['user_js_support'] = FALSE;

?>
<script type="text/javascript">
    var XHR;
    if (window.XMLHttpRequest){
        // The code for IE7+, Firefox, Chrome, Opera, Safari
        XHR=new XMLHttpRequest();
    }else{
        // The code for IE6, IE5
        XHR=new ActiveXObject("Microsoft.XMLHTTP");
    }
    XHR.open("GET","http://127.0.0.1/check_js_user_support.php<?php echo '?PHPSESSID='.session_id(); ?>",true);
    XHR.send();
</script>
<p>
    <a href="<?php echo '?PHPSESSID='.session_id(); ?>">
        Refresh
    </a>
</p>

Create another file called check_js_user_support.php and put this code inside:

<?php

    if(isset($_GET['PHPSESSID'])) session_id($_GET['PHPSESSID']);
    session_start();

    $_SESSION['user_js_support'] = TRUE;

?>

Copy both files in your local web server root. Open the page ajax_js_enabled_test.php from your browser. The AJAX request starts and the page check_js_user_support.php will set the session param called user_js_support to TRUE. So by pushing the Refresh button the page will be reloaded, the $_SESSION['user_js_support'] will be TRUE and the script will write: "Javascript enabled"