Using the following tutorial I want my website to use AJAX to load the content (but also want to be able to use the back button etc. etc):
http://www.queness.com/post/328/a-simple-ajax-driven-website-with-jqueryphp
Ofcourse if someone has javascript disabled the website should also work (without Ajax).
The problem however comes when a javascript enabled user sends a link to a non javascript enabled user. Because javascript is disabled it will not handle the #-tag correctly and will just go to the homepage (so linking directly to pages from a javascript user to non-javascript user is impossible). Is there a way to resolve this issue (preferably php or htacces).
HTML5 gives us methods to alter the URL without refreshing the page https://developer.mozilla.org/en/DOM/Manipulating_the_browser_history#Adding_and_modifying_history_entries
This means you can update something without a page refresh but still give the user a url they can bookmark or send to someone else. These urls will work without JavaScript, as long as you have pages at those locations or are catching them with mod_rewrite or similar.
https://github.com/browserstate/history.js is a great little pollyfill which will use the HTML5 history stuff if the browser supports it, otherwise (Internet Explorer) it changes the hash of the url.