title: getElementByClass().setAttribute doesn't work
body: <p>why when i write</p>
  
  <pre><code>document.getElementByClass('home1').setAttribute('style', 'background-image:url(img/red_menu.PNG);');
  </code></pre>
  
  <p>it doesn't work?
  i have the element with <code>class="home1"</code></p>
  
  <p>with <code>document.getElementById('home1')...</code>
  works fine
  thanks</p>