Disabling School Web Filter

just yestarday i somewhat figured out how to disable the schools web filter by using javascript in the addressbar heres the code i used:

javascript:void('filter')

i have no idea if it actually disables the filter or just all javascript itself my question is would this be a valid line of javascript.i already know about firefaux and all those sites but i just wanted to figure this out.

it would only be valid if the site you are on had a section or command called filter. for instance, javascript:void(document.cookie); will disable the cookie, which is a document on the site. the site wouldn't have a filter to block you from it, now would it?

thats what i thought but for some reason it works. im thinking that maybe its just ignoring "filter" and disabling javascript in all. and its not a software filter like the content settings in internet explorer, its an actual network filter on the entire schools network so even if your using your own computer it still blocks it. i know cause i tried to go to a blocked site on my psp and it still blocked it. heres the link to the acutal block page that comes up when you try to visit a blocked site:

http://www2.hbuhsd.org/webblocked.htm