This feature would only be available if piwik.js finds the Modernizr (http://www.modernizr.com/ ) library has been loaded.
Could we add change "Plugins" to "Browser features" and add HTML5 and other things in this bucket?
Could we get the html5 detection code from Modernizr and have it included in piwik.js directly?) - requiring another library is not practical (maintenance, more complicated setup, etc.)
Some of the HTML5 detection features requires adding elements to the DOM. Plus, the minified code is about 8K. This would double the size of minified piwik.js.
Not all browsers support all the features of HTML5. How do we count partial support?
The alternative is to identify HTML5-compliant browsers by user agent (e.g., minimum AppleWebKit/Gecko/MSIE version).
see http://diveintohtml5.org/detect.html#video-formats for some code to detect HTML5 features.
I don't think we can detect 'HTML5', but we could detect specific HTML5 features, I think this would make sense and add value to Piwik.
You may well ask: How can I start using HTML5 if older browsers dont support it? But the question itself is misleading. HTML5 is not one big thing; it is a collection of individual features. So you cant detect HTML5 support, because that doesnt make any sense. But you can detect support for individual features, like canvas, video, or geolocation.
Users interested in a specific html5 feature can use modernizer and a custom variable.