title: Change style of all elements of a class via prototype javascript
body: <p>This is probably really simple, but the prototype docs on the $$(function) really suck. What do I DO with all the items once the function gives them to me?</p>
  
  <p>First I tried:</p>
  
  <pre><code>$$('div.category').style.height = 400 +"px";
  </code></pre>
  
  <p>Then:</p>
  
  <pre><code>$$('div.category').each(.style.height = 400 +"px");
  </code></pre>
  
  <p>Finally:</p>
  
  <pre><code>for (x in $$('div.category'))
  {
      x.style.height = 400 +"px";
  }
  </code></pre>
  
  <p>None of them are working. Help?</p>