title: Using Modernizr library, why does it add classes to the html tag
body: <p>Can anyone explain (because the github page doesn't) why Modernizr feels the need to add all of those classnames to the HTML tag ? After loading Modernizr, it looks like this:</p>
  
  <pre><code>&lt;!doctype html&gt;
  &lt;html class=" js flexbox canvas canvastext webgl ~~~~ etc etc
  </code></pre>
  
  <p>I see no explanation at all why it wants to do that. Modernizr provides properties to let me know whether for example canvas is supported (Modernizr.canvas == true?). Are those html classnames added for a test that's easier than that?</p>