title: Animated Collapse of Webpage Sections
body: <p>I've just started with JavaScript, and I would like to implement an animated collapse of certain sections of the page.</p>
  
  <p>Across the top of my page I have a nav bar that contains links to all of the sections of the page. What I want to happen when I click one is:</p>
  
  <ol>
  <li>The currently displayed section collapses to nothing</li>
  <li>The requested section expands (ideally simultaneously) to fill the remaining space</li>
  <li>The URL to change reflecting this new selection</li>
  </ol>
  
  <p>I want number three so that it elegantly downgrades if JavaScript is not installed, and so that if someone opens it in a new tab it still works.</p>
  
  <p>So how would I go about implementing this? Is this possible/sensible to do with just JavaScript? Or do I really need to go about learning PHP? (I know ASP.NET, but don't have it on my server)</p>