title: How to append to HTML5 localStorage?
body: <p>I do a</p>
  
  <pre><code>localStorage.setItem('oldData', $i("textbox").value);
  </code></pre>
  
  <p>to set the value of key <code>oldData</code> to the value in a textbox.</p>
  
  <p>The next time something is entered to the textbox, I want to append to the already existing <code>oldData</code>.</p>
  
  <p>So, if I enter <strong>apples</strong> and then <strong>oranges</strong> in my textbox, my localStorage key <code>oldData</code> should look like this:</p>
  
  <p>Initially:</p>
  
  <pre><code>Key      |   Value
  ---------------------------
  oldData  |  apples
  </code></pre>
  
  <p>Now:</p>
  
  <pre><code>oldData  |  apples oranges
  </code></pre>
  
  <p>How can I append? <strong>Is there an <code>append</code> method provided?</strong></p>
  
  <p>Or do I need to read the data first, append in javascript and then write back?</p>