url ajax lookup

no clue what im looking for, so if you can tell me what this is, what i should lookup for this.

http://web开发者_运维问答site.com/page.php#article23

The Number sign isnt a url request, like GET or POST, its more of a "Ahref Name", but this was with ajax, where it would change the whole frame, wondering what its called.

the # seperates the URI from the fragment identifier. See link text