Firefox 3.0.1 running on Kubuntu 8.04 Live CD
Firefox uses the Gecko layout engine (also called a rendering engine) for displaying web pages and its user interface too, by rendering XUL, an XML user interface language providing widget definitions. Gecko 1.9 is used in the last stable Firefox release. An unofficial port of Firefox using Qt instead of XUL is in the works too, and I'm very curious how development will evolve.
Compared to browsers which use different engines, like Konqueror 3.5.9 or Opera 9.52, Firefox performs better than the first when submitting or filling up certain forms, but it seems slower loading web pages than Opera. Konqueror 3.5.9 (which uses KHTML) fails miserably for example allowing you to send mails using certain forms or even writing a Blogspot post, while Firefox has no problems regarding this matter. On the other hand, despite the fact that it was praised and announced to have a lot of speed improvements, Firefox still eats more CPU and memory resources than either Konqueror or Opera, making it the slowest of them three. Although it has slow loading times and a slow interface, once loaded and in action, Firefox will prove the best tool for finishing any web-related task, also having the big advantage over Opera for being open-source.
The interface hasn't changed much compared to previous versions, like the 2.x series. It's clean, simple and intuitive, providing only the necessary toolbar buttons and most useful options via the Preferences window. A good improvement version 3 has is the address bar, which now offers clever ways of accessing the desired location, depending on how many times you accessed it and how relevant the content is compared to what you type.
It has a bookmark toolbar for fast access to your most used addresses, and provides the classic Back, Forward, Reload, Stop and Home buttons. To the right of the address bar is located the Search Engines feature, which can be accessed using CTRL+K and allows you to search by default on Google, or select another search engine, like Amazon.com or Wikipedia. Many other engines can also be installed, but I think user-defined keyword shortcuts are more useful and handy. It's a matter of preferences after all.
The Preferences window allows configuration of the most usual settings, like the default address to start with, download location, tabs configuration, appearance or security (including privacy settings, cookies, and passwords). The interface fonts can be changed using the userChrome.css file inside the Firefox directory (e.g. ~/.mozilla/firefox/RANDOM.default/chrome/userChrome.css).
Preferences - you can change the most usual settings hereThe about:config dialogue allows you to truly configure Firefox in any way possible, and you can find here all the necessary entries for tweaking Firefox the way you like it. For example, if you want to disable the finished downloads notification, all you have to do is search for the browser.download.manager.showAlertOnComplete variable and set its value to false by double clicking on it. A very comprehensive guide for each entry can be found here.
The about:config entries - tweak anything related to Firefox from here
One of the great features Firefox comes with is the ability to install various add-ons and themes, and the official website contains hundreds of them, like the StumbleUpon add-on, the DownloadHelper add-on for downloading all media content from within a web page (useful especially for YouTube videos), or the Adblock Plus extension which blocks ads on pages including them. Some of the nicest themes already ported to Firefox 3 are Noia eXtreme and Phoenity Modern.
Regarding interface speed, response and loading times, I think Firefox still remains one of the slowest browsers compared to Konqueror, Opera or Epiphany. I didn't yet have the occasion to compare it to Chrome, but since currently it's only natively available for Windows, running it through Wine shouldn't be fair.
About Firefox 3
In the end, Firefox 3 looks to be the most powerful and useful browser available for the Linux platform. Opera is a very good competitor regarding features and usability, but unfortunately it's still closed-source. All the themes, all the powerful entries in about:config, the add-ons, the bookmarks easy to manage, all these features make out of Firefox the best and the most popular web application for the Linux OS.
5 Useful Tips to Customise Firefox 3
Updated: Sep 16, 2008