title: what is the meaning of no-js class in html5
body: <p>i seen lot of website have specific code for ie6, ie7,ie8. </p>
  
  <pre><code>&lt;!--[if lt IE 7 ]&gt; &lt;html lang="en" class="no-js ie6"&gt; &lt;![endif]--&gt;
  &lt;!--[if IE 7 ]&gt;    &lt;html lang="en" class="no-js ie7"&gt; &lt;![endif]--&gt;
  &lt;!--[if IE 8 ]&gt;    &lt;html lang="en" class="no-js ie8"&gt; &lt;![endif]--&gt;
  &lt;!--[if IE 9 ]&gt;    &lt;html lang="en" class="no-js ie9"&gt; &lt;![endif]--&gt;
  &lt;!--[if (gt IE 9)|!(IE)]&gt;&lt;!--&gt; &lt;html lang="en" class="no-js"&gt; &lt;!--&lt;![endif]--&gt;
  </code></pre>
  
  <p>and i seem html have specific class like this </p>
  
  <pre><code>&lt;html class=" js no-flexbox flexbox-legacy canvas canvastext webgl no-touch geolocation postmessage websqldatabase indexeddb hashchange history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients cssreflections csstransforms csstransforms3d csstransitions fontface generatedcontent video audio localstorage sessionstorage webworkers applicationcache svg inlinesvg smil svgclippaths"&gt;
  </code></pre>
  
  <p>any one just tell what is the use this codes</p>