This blog post is a part of Mobilizing websites with responsive design and HTML5 tutorial. For all posts please see the Introduction post.
Firefox Mobile and Opera Mini are popular after market browsers the user can install on their device. They offer additional functionality and speed over the stock browsers. You should also test your mobile sites with these browsers.
There also exist plethora of other after market browsers, especially for Android platform. I am not sure how popular they are, but they all are based on the same WebKit engine shipped with the Android platform, so they generally yield the same rendering output as the Android Browser stock browser does and separate testing is not needed.
1. Opera Mini
Opera Mini has over 100 millions users and it is the most popular mobile web browser.
The thin client strategy in web page rendering is also used by Kindle Fire.
2. Opera Mini simulator
Opera Mini Simulator is a Java applet which you can run in your web browser.
3. Opera Mini on devices
You can install Opera Mini on any device, including low-end phones and iOS devices.
Sadly, Opera Mini offers little debugging tools because the pages are rendered on remote servers. Your best shot is use Opera Mobile to render the pages, as the underlying Presto rendering engine is the same.
4. Opera Mobile (not mini)
Opera Mobile (not mini) is a full browser which you can install various handsets, including Android, Nokia and Windows Mobile.
Opera Dragonfly debugging tools support remote debugging on the mobile devices. You can use desktop debugging tools to inspect a page running in a mobile phone. A very handy feature for all mobile web developers.
5. Firefox Mobile (a.k.a. Fennec)
You can install Firefox Mobile on Android devices. There also exists community maintained port for Meego mobile platform and unofficial builds for iOS and webOS. The current builds use native Android UI and mobile optimized version of Gecko rendering engine. For more complex (web) pages the speed of the browser beats Android Browser stock browser. Firefox Mobile is also the only currently shipped mobile browser supporting WebGL.
A Firefox Mobile PC built exists for Microsoft Windows, OSX and Linux and is suitable for testing purposes. Note that some effort might be needed to make it run, as these builds are not officially supported.
Download instructions for PC/Mac: