Jquery.get() not working in IE8/9. Won't load cached pages 304 not modified
Change this line:
var new_url = $(this).attr('href')
To this:
var new_url = $(this).attr('href') + '?' + Math.random();
This is called a "CacheBuster" and effectively creates a url similar to:
"website.com/page.html?1241233"
That random number will be different for every click of ".ajax_link" so IE will think its a new page and get it properly.