将javascript数据存储到PHP SESSION VARIABLE中？

I'm wondering if it's possible to store a number generated from a javascript script into a PHP SESSION variable. I basically want to store my code '+.res.id+' and '+.res.level+' into a PHP SESSION. Those 2 javascript codes generate a random number and inputs that number in a html form. IS there anyway I could take that number and store it in a PHP SESSION? For example

<script>
JAVASCRIPT CODING

'+res.level+'
'+res.id+' // BTW it actually does generate a number I just can't echo it in another      page or store it in a SESSION 
</script>

<?php
$_SESSION['.res.id.'] = $idnum;
$_SESSION['.res.level.'] = $levelnum;
?>

Then after in a seperate page I want to call that SESSION and echo the number that the code generated. But my only problem is that when I echo the $_SESSION it echo's as ".res.id." instead of the randomly generated number. How do I fix this to make it echo the random generated number?

First of all javascript is running on a client side and php is running on a server side. It means you can't just store the generated number. But there is a workaround on that. You can do that by means of AJAX request.

In your js you can do this.

var res_id = your_random_number;
var res_level = your_random_number

$.post("/any/url/that/contains/your/php/code", {res_id:res_id, res_level:res_level});

In your php.

$_SESSION["res_id"] = $_POST["res_id"]; 

$_SESSION["res_level"] = $_POST["res_level"];