title: Changing Placeholder Text On Focus
body: <p>Is there a simple solution for changing placeholder text when an input is in focus? For example:</p>
  
  <pre><code>&lt;input type="text" placeholder="Join our mailing list!"&gt;
  </code></pre>
  
  <p>would become this:</p>
  
  <pre><code>&lt;input type="text" placeholder="enter your email address..."&gt;
  </code></pre>
  
  <p>while the input is active.</p>