Have you already installed Java for the actual operating system or is it completely disabled? I would suggest downloading and installing this first and see if your issue resolves.

If it is already checked , I'm still thinking of solutions.

Which web site are you having issues opening?

JavaScript does not require any extra installation as it handled by the browser itself.

IE7:

Internet Options - Security - Custom Level - Scripting/ActiveScripting must be set to "Enable"

Firefox 3:

Tools - Options - Content - Enable Javascript

Try this link:

http://liblearn.osu.edu/tutor/jscript.html

If you see a pop-up, that means javascript is good and enabled so it's a problem with your website, not your settings.