Oh. My. God. I have had NoScript enabled which pretty much claims to do the same thing, but it still seems to slow the browser down considerably. Not to mention the constantly nagging dialog boxes.
If you actually turn off Javascript in Firefox like so (see image), the browsing speed increase is tremendous. I was surprised myself.
Sure, it feels like you’re surfing the web in 1997 and I had to turn Javascript back on in order to be able to upload the above image to this posting, but boy is it quick.
And I suspect that there is _a lot_ of room for speed improvement with clever coding. Come on coders!! Do it! Save those CPU cycles!