Although its no Internet Explorer, Firefox still has security holes. The thing is, many of these flaws come from the scripting support, such as support for javascript or Flash. The obvious way to fix this is to turn off scripting, but by default that happens to be an all or nothing proposition. That’s where NoScript comes in handy. NoScript automatically blocks all scripts by default, which you can then manually white list by site. At first this dramatically slows you web browsing, but after having built up a list of web sites you visit regularly, it fades away into the background, requiring little effort to deal with.

Although I strongly recommend installing NoScript on Firefox for the benifits it provides, it does not have a spotless record. I previously mentioned issues with running NoScript when you self-host a website, and even before that NoScript was modifying another addon, AdBlock, without user permission so that advertisments on the NoScript site still showed. Despite this, NoScript still provides some of the best performance for Firefox security.