Firefox 4: another browser testing headache?

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22 March 2011

Mozilla has released Firefox 4. Will this new browser upgrade cause more headaches for website operators?

Firefox logoHot on the heels of Microsoft's IE9, Mozilla has today released Firefox 4 (FF4).

Much like IE9, Firefox brings a series of UI improvements and speed enhancements for browser users.

But if you run a website, does a major new release of Firefox carry the same risks as the release of IE9?

The short answer: probably not.

The longer answer: The Internet Explorer rendering engine (Trident) has a huge legacy of quirks and non-standard behaviours that Microsoft needs to continue to support when they release a new browser.  This is one of the reasons why recent versions of IE have had a "compatibility mode". 

The Firefox team doesn't have this legacy because its rendering engine (Gecko) has been focused on standards compliance for much longer. By focusing on continuing standards compliance they have been able to create a more stable progression between browser versions.

(For similar reasons the rapid release philosophy of the Chrome development team, which shares a rendering engine (Webkit) with Apple's Safari browser, also poses a reduced risk of breaking your website.)

However, the latest release of Firefox is still a major change from previous versions, including changes in the Gecko rendering engine, and for that reason we recommend cross-browser testing - i.e. testing your website in more than one browser, including both FF4 and IE9.

If you'd like to do your own cross-browser testing for FF4, you can download FF4 here. Or, contact us and we'll check your website for you, in all the major browsers, for free.

PS... we include cross-browser testing as a standard part of developing a website, and it's the sort of thing we can do on an on-going basis as part of our website support and maintenance service.