The best Rated 5 out of 5 stars
I believe it is no exaggeration to say that this app is the best Firefox has to offer. Together with AdBlock it is the reason why many informed users turn to Firefox in order to browse. Be warned though: if you visit bank sites, shopping sites and elsewhere where you need to make online payments, these apps can cause issues (obviously) so you should turn them off there.Alternatively use other browsers (e.g. IE) to visit such sites. But when it comes to safe browsing use Firefox with these two apps installed.
The learning curve of NoScript can be quite high, though it all depends how deep you want to go. In other words, you will most likely be OK in most cases by simply doing nothing.
I should also mention that this app is updated on a regular basis, something essential for this type of security app.
Again, this is (without an exaggeration) the best app for Firefox.