This used to be problem only for IE but now I have seen this all over the place, so just to be save, I recommend applying this fix to all of your ajax get requests. The idea is to add a unique query string parameter to fool the browser into thinking that you are making different requests each time, so adding a random number will do it. To make this robust, you want to detect if the link already has a query string param, so that you are not appending "?" to already existing query string. The "url.indexOf('?')" will do the job of "contains()" in other languages. So here we go, here is the final code:
if(url.indexOf('?') < 0){
url = url + "?_r=" + Math.random() * 5;
}
else{
url = url + "&_r=" + Math.random() * 5;
}