title: What's the good practice to add html content of popup box in JS code?
body: <p>I'm new to HTML and javascript. When I try to initiate a popup window, I find the usual way to do is like this:</p>
  <pre><code>var popup = new Popup(title, content);
  </code></pre>
  <p>where <code>content</code> is string of html containing the content of the popup box, such as</p>
  <pre><code>var content = &quot;&lt;div&gt; \
  &lt;input type='text'&gt; \
  &lt;/div&gt; &quot;
  </code></pre>
  <p>This writing style is really ugly, and when the content gets complex, the code is hardly readable. What's the good practice for doing this?</p>
  <p><strong>Edit</strong>
  By popup I didn't mean a new browser window, but something like when you click on a pin on Google map, detailed information about that pip will pop up.</p>