title: .appendChild is not a function
body: <p>I'm trying to add some elements to the DOM, but the FireBug console keep alerting me for an error saying <code>TypeError: el.appendChild is not a function; el.appendChild(para);</code> So here is the js: </p>
  
  <pre><code>var para = document.createElement("tr");
  var node = document.createTextNode(data.filename);
  para.appendChild(node);
  var el = document.getElementsByClassName("toBeSelected");              
  el.appendChild(para);
  </code></pre>
  
  <p>Found some common problems but couldn't find a way to solve mine.</p>