Detecting Back Button/Hash Change in URL

Question

I just set up my new homepage at http://ritter.vg. I'm using jQuery, but very minimally.
It loads all the pages using AJAX - I have it set up to allow bookmarking by detecting the hash in the URL.

 //general functions
 function getUrl(u) {
      return u + '.html';
 }
 function loadURL(u)    {
      $.get(getUrl(u), function(r){
                $('#main').html(r);
           }
      );
 }
 //allows bookmarking
 var hash = new String(document.location).indexOf("#");
 if(hash > 0)
 {
      page = new String(document.location).substring(hash + 1);
      if(page.length > 1)
        loadURL(page);
      else
        loadURL('news');
 }
 else
      loadURL('news');

But I can't get the back and forward buttons to work.

Is there a way to detect when the back button has been pressed (or detect when the hash changes) without using a setInterval loop? When I tried those with .2 and 1 second timeouts, it pegged my CPU.

Answer 1

The answers here are all quite old.

In the HTML5 world, you should the use onpopstate event.

window.onpopstate = function(event)
{
    alert("location: " + document.location + ", state: " + JSON.stringify(event.state));
};

Or:

window.addEventListener('popstate', function(event)
{
    alert("location: " + document.location + ", state: " + JSON.stringify(event.state));
});

The latter snippet allows multiple event handlers to exist, whereas the former will replace any existing handler which may cause hard-to-find bugs.