HTML5 is pretty new to the web and not all sites use it. Finding out whether a website uses HTML5 is not always obvious. If you are interested in Web Technologies, you’ll dig this extension called HTML5 Powered.
All it does is display the HTML5 logo in the browser whenever you visit a webpage containing the HTML5 doctype. Pretty simple, right? Have a look at the screenshots below to see how it works.
HTML 5 Powered is available for Google Chrome and Opera.