How to add self-signed certificates to different browsers?

What is the difference between add-ons, plugins and extensions for web browsers?

• While using Mozilla Firefox, I felt the need to add a functionality in my browser, but while I checked out the settings, I found three options, add-ons, plugins and extensions. What is the basic difference between all of them. If I want to view the page rank of a http://Finoit.com website or watch a Youtube video, etc., which of these facilities would be feasible? What about other browsers such as Chrome, Safari, etc., do they also provide such capabilities?

• Answer:

  Plugins are external pieces of software that work in tandem with certain programs to offer additional function. Eg, flash player is a plugin because flash is not a program installed in your browser; it is a bit of software installed separate;y which then works with the browser to render flash content. Similarly many media players have plugins which work with the browser to support certain file formats such that they can be played in the browser. So in your question, watching a youtube flash video would require a plugin. Add-ons and extensions in Firefox are the same thing as far as I know. Addons are small pieces of software installed to work WITHIN the browser to allow it to perform certain additional functionalities and features not already available in the vanilla browser (pure browser installed fresh off the exe). In your question, an addon would be a small icon next to the address bar which shows the page rank of the page you're looking at or it could be something that displays the page rank within the web page itself. As far as I can see from the menus, extensions are simply the addons you have already installed to Firefox. I think the difference is merely terminology. Not having used Safari, I don't know about whether it supports extensions or addons but Chrome most certainly does. Chrome Web Store is a site just like the addons page for Firefox which is a marketplace for user-created extensions (that's what addons are called in Chrome). I have an extension that records all the tabs I have closed and creates a popup when I click a button to my top right which lists all the pages I've closed. A screenshot of an extension on Chrome for Orkut (apparently it still exists) Edit: Apparently there are some minor differences as explained here http://stackoverflow.com/questions/2041261/what-is-the-difference-between-a-firefox-extension-and-a-firefox-add-on