JavaScript - - By Simon Willison

Which browsers to support?

Dave Shea’s Browser Support 2004 looks at today’s browser market, and discusses his approach to testing sites in different browsers. Dave makes some great recommendations and I can’t say I disagree with any of them. That said, here are a few thoughts of my own.

Firstly, sites like are fine for checking out browser trends, but have very little value in deciding which browsers to support. works by aggregating statistics from all of the sites that use their free stats counter. Unfortunately, sites that use this service are biased strongly towards people who use free hosting services. Mainstream and professional sites rarely use free counters to track their traffic, and as a result is unlikely to provide a truly accurate indication of global trends. I’ve always said that the only reliable way of deciding which browsers deserve your support is to look at the statistics for your own site. As an example, nearly 50% of visitors to my personal blog are using a Mozilla variant – compared to a global average from of less than 2%.

Let’s also look at what “supporting a browser” actually means. By Dave’s definition, a browser you support is one that you actively test and make an effort to ensure your site’s design works as you want it to. It’s important to note that specifying a list of supported browsers does not mean deliberately avoiding support for others – it just means that you won’t personally test them and you don’t mind if the site design doesn’t function entirely as planned.

Thanks to CSS and web standards it’s actually possible to create good looking sites that are accessible (in that the site content can be retrieved) from virtually any browser still in use. The trick is to use progressive enhancement, a methodology advocated by WaSP founding member Steven Champson. Start with the core structural markup of a page and build additional presentational and behavioural information using CSS and Javascript. The end result is a great looking page with all of the bells and whistles expected of a modern site, that never-the-less is still accessible to people using even the most out-dated technology.