The first thing I'd suggest is to have a look at the source code, using the browser's "view source code" option. You will find that the html is just a shell. There is virtually nothing there. So it will probably validate as HTML5 anyway!
Then you might want to validate the html and css using the W3C validators. I've just done that and there were 4 html errors and 29 css ones. You can either use the valiidators directly, or use the shell on my site: www.emberwebsites.co.uk/html/ which will run the html, css and link validators in one go.
I specifically used the new HTML 5 3D canvas, also called WebGL(TM) to animate
HTML elements. For me this was very attractive, because with
3D canvas you can download programs into the GPU and so
Because 3D canvas, however, does not run everywhere, there
is a fall back into 2D canvas. The site is about an open source lib
for this purpose: http://www.taccgl.org
HTML5 is a newer version and it has advance features as CSS3 has. It has a great impact on RWD that is responsive web designing that is useful to optimize the websites on all devices like smartphones as well.
http://etreading.com/ This is the first site I built for my neighbor/customer. I started learning html 5 and css3 about a month ago, so this is what I know so far. My site does support IE. Although, it took awhile to find out why IE didn't work when I first launched the site. I finally figured it out. When I was first building the site, I was using Chrome for test purposes, but I see that the site works with safari, chrome, firefox, and ie. I would say that this site would fall under reference and sales. It is informative, and the author is trying to sell something.
HTML5 is often compared to Flash, the two technologies are very different. Both include features for playing audio and video within web pages, and for using Scalable Vector Graphics.HTML5 is the XML serialization of HTML5. XML documents must be served with an XML . XHTML5 requires XML's strict, well-formed syntax.