title: What is the 'data' in window.history.replaceState
body: <p>We are working on a project using window.history.replacestate. Unfortunately we aren't very good at javascript.</p>
  
  <p>Essentially we are using it to replace any number of shortlinks to the 'root' link. For example :</p>
  
  <pre><code>domain.com/fJfk8
  domain.com/9dkDl
  domain.com/fjgdD
  </code></pre>
  
  <p>would all 'appear' as :</p>
  
  <pre><code>domain.com/nice_url
  </code></pre>
  
  <p>It doesn't have to work so we'll put the javascript in the page and in the browsers it does then great and if it doesn't, they get the shortcode. </p>
  
  <p>Note : we <em>don't</em> want history !</p>
  
  <p>So we are just using :</p>
  
  <pre><code>window.history.replaceState('Object','Nice URL Title', '/nice_url');
  </code></pre>
  
  <p>The question is that this appears to work but we don't understand the 'Object' (data) part. </p>
  
  <p>What exactly is it ? </p>