Are you asking about Head First HTML5 Programming? It's not clear from your message.
If you are, we recommend running the examples in the book on the most recent versions of each of the modern browsers (Chrome, Safari, Firefox, Opera and IE). We do indicate in the book where there may be specific issues with a browser, but most examples will work on most browsers assuming you're using recent versions. (Although I just found out that Firefox 8 broke web workers, where they were working in Firefox 7!). Anyway... we also recommend using Modernizr to test for HTML5 features and provide graceful fallback options for browsers that don't support a given feature.