Firefox 5 hands-on review

Mozilla has pushed out an update to its browser in the shape of Firefox 5, but users will notice little difference over the previous version, with most changes coming under the hood as security and stability fixes.

Available to download from Mozilla.org now, or via Firefox's own automatic update tool, version 5 is an 8.5MB download that installs as smoothly as every other update we have tested.

However, despite the jump from 4.0.1 to 5, there does not seem to be a huge difference between the two versions, at least not in appearance.

In fact, the only visible difference is the addition of a check box on the 'Privacy' tab of the Options menu making it easier for users to enable or disable the 'Do Not Track' feature introduced in Firefox 4.0. As before, this simply flags up to web sites that you do not wish to be tracked, and relies on the site itself to respect your wishes.

As with previous Firefox updates, Mozilla claims a boost in performance and better support for new technologies such as HTML5, along with a number of bug fixes.

We ran Firefox through the commonly quoted SunSpider test for JavaScript performance, and found an improvement of 34.1ms with the benchmark returning a result of 330.8ms for Firefox 5 compared to 364.9ms on Firefox 4.0.1. Both tests were run on the same Windows 7 PC  – a boost of about 10 per cent.

Also new is support for CSS animations, which allows web site developers to produce simple animations, without the need to resort to JavaScript code. Not many web sites will have support for this feature at present, so Mozilla has a developer page with a handful of basic examples showing scrolling text moving across the page and growing and shrinking in size.

On the security side, Firefox 5 also addresses some concerns over the WebGL API for in-browser 3D graphics by blocking the use of cross-domain elements as the source for WebGL textures. Mozilla warned that this may break some pages that already use WebGL.

As with previous releases, Firefox 5 still supports Windows XP, which is a bonus for users still running the older platform, and we found no problems with the add-ons that we have installed.

In summary, Firefox 5 does not appear markedly different from a users' perspective, but upgrading is but a moment's work and the security and stability changes mean it is worth having if you are a regular Firefox user.