title: window popstate event not working in safari
body: <p>I have tried to disable browser back button by this code :</p>
  
  <pre><code>&lt;script&gt;
      //disable back button
      history.pushState(null, null, ' '); 
      window.addEventListener('popstate', function () {
          history.pushState(null, null, ' ');
      });
  &lt;/script&gt;
  </code></pre>
  
  <p>It works in <strong>Chrome</strong>, <strong>Mozila</strong>, <strong>IE10</strong>, but does not work for safari(5.x).
  <br>Has anyone achieved this before crossbrowser ?</p>