Add php session var to javascript

Hello, its very simple for someone who know this. I have a php file with a javascript code between (head) and (/head) tag. This code post info to a second php file where I need to get my $_SESSION`'id' variable So add my SESSION variable in the javascript code then get it in the second file to call my MySQL query. BID SHOULD BE UNDER 7$ i WILL AWARD IT VERY FAST AT THE LOWEST BIDDER WHO TELL THAT HE CAN DO IT IN THE NEXT MINUTES. Thank you