i just downloaded firefox and now anything that uses javascript doesn't work. youtube, myspace etc...
whats wrong?
javascript is enabled. still nothing.

Not much of a FF fan myself, but if I remember correctly, javascript is disabled by default.
You can enable it by going to Tools -> Options.
Select the content tab, and check the box beside "Enable Javascript".
Hit Ok, and you should be good to go, but it may require you to close Firefox and reopen it.

tools/options/content/...make sure check marks are there to enable all in java .. restart