title: document.getElementsByClassName() not working like getElementById does?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/10693845/can-getelementsbyclassname-change-style">Can getElementsByClassName change style?</a>  </p>
  </blockquote>
  
  
  
  <p>I am trying to "fix" the "new" YouTube using Greasemonkey, I've been getting things to work as they should when it's with ID's, however I have been unable to modify anything with a class, it appears I am unable to select it or whatever anyways.</p>
  
  <p>I have been trying to use:</p>
  
  <pre><code>document.getElementsByClassName("video-extras-sparkbar-likes").style.height='10px';
  </code></pre>
  
  <p>However it isn't working. :\</p>
  
  <p>I'm not very familiar with Greasemonkey and what not, so would there be a reason why though my browser supports this, Greasemonkey may not?</p>