Passing PHP variable into JavaScript [duplicate]

I've a PHP session variable, $_SESSION['user'], alive throughout the session. In the head section, I've my JavaScript file included, scripts.js.

How do I pass the session variable into the JavaScript file if I want something like the following.

$.("#btn').click (
     function() {
        alert('<?php echo $_SESSION['user']; ?>');
     }
)

As the <?php ?> isn't recognized in the JavaScript file, the code above doesn't work. So I've to put in the PHP file itself, but how do I keep it in the JavaScript file?

Solution 1:

In your PHP file you could set your user as a global varibale:

<script type="text/javascript">
    var ptamzzNamespace = {
       sessionUser : '<?php echo $_SESSION['user']; ?>'
    }        
</script>

Include this before including your external JavaScript code.

Then in your JavaScript file you can use it:

$.("#btn').click (
     function() {
        alert(ptamzzNamespace.sessionUser);
     }
)

Additionally: If you're not sure if your session varibale can contain quotes itsself, you can use addslashes() to fix this problem:

<?php echo addslashes($_SESSION['user']); ?> even if this will maybe produce something you don't really want to display (because it produces a string with slashes) it will help that your code will not fail. (Thanks to Artefacto)

Would this be an option for you?

Solution 2:

Set the userID (in PHP) in an input type hidden in your file. In your JavaScript code you can read the hidden input types value.

Solution 3:

You could set your server up to parse .js files as PHP. For example, in Apache config or .htaccess file:

<FilesMatch "scripts.js">
    AddHandler application/x-httpd-php5 .js
</FilesMatch>