title: Set style using pure JavaScript
body: <p>I want to set body's background without jQuery.</p>
  <pre><code>jquery : $('body').css('background','red');
  </code></pre>
  <p>Why won't this work in pure JavaScript?</p>
  <pre><code>document.getElementsByTagName('body').style['background']  = 'red';
  </code></pre>