如何在不浏览页面的情况下更改浏览器中的URL？

I am writing a complex AJAX application at the moment and the entire site has clean URLs. At the moment PHP creates the basic layout for each page however I don't want to have to navigate away from each page when the user clicks on a link, and I don't want to have a hash in the URL because it won't fit with the rest of the site. I know that this has cropped up loads before on the site and it seems to be quite commonly asked but I was wondering if there was a neat HTML5 way of just appearing to change the URL in the address bar even if it technically remains on the same page.I am writing a complex AJAX application at the