Therefore, it is probably better to create your website and pages in such a way that Javascript is essential for it to perform. That way the user needs to enable Javascript to get anywhere. In my opinion, if a user today wishes to disable Javascript or uses a browser that does not use Javascript, then that user has no business looking at my pages :)
Because of XSS, it is not uncommon for Users to disable Javascript altogether or to use NoScript to selectively disable it.
There are also still a significant number of PDA and cell phone browsers that do not support Javascript. And visually-disabled Users might be using a speech-based or otherwise-specialized browser that cannot execute Javascript.
Saying that Users have to have Javascript turned on to use your site is all fine and good, but is it worth it to to have to maintain code that functions differently in each browser just so you can alienate 4% of your User base?