How to remove PHPSESSID?

I found that there has a PHPSESSID in my site's URL, it's not SEF, so how to remove it?
Thanks in advance

 

OK you'll have to be more specific. What type of site is it ? Do you run some forum script ? If yes which one.

 

Below is my site, please take a look,thanks

http://www.javaresources.org/showcategory.php?cid=21&PHPSESSID=5a482c43f045396de092f0d6687b8b6a

Code (markup):

 

Try adding this line on top of your script.

ini_set('url_rewriter.tags', null);

PHP:

Or

ini_set('session.auto_start', '0');

PHP:

if your site doesn't require sessions, but it's enabled by default.

Note that the URL rewriting is required for users who don't have cookies enabled.