I am following a book example hence the code is very simple.
This is the code:
jQuery.get(\"ajax_search_results.php\",
{ s:search_query },
This is supposedly because you trying to make cross-domain request, or something that is clarified as it.
You could try adding header('Access-Control-Allow-Origin: *'); to the requested file.
Also, such problem is sometimes occurs on server-sent events implementation in case of using event-source or XHR polling in IE 8-10 (which confused me first time).