title: What do querySelectorAll and getElementsBy* methods return?
body: <p>Do <code>getElementsByClassName</code> (and similar functions like <code>getElementsByTagName</code> and <code>querySelectorAll</code>) work the same as <code>getElementById</code> or do they return an array of elements?</p>
  
  <p>The reason I ask is because I am trying to change the style of all elements using <code>getElementsByClassName</code>. See below.</p>
  
  <pre><code>//doesn't work
  document.getElementsByClassName('myElement').style.size = '100px';
  
  //works
  document.getElementById('myIdElement').style.size = '100px';
  </code></pre>