服务器端AJAX请求的排队机制

I have been struggling with a situation on a site where users' clicks generate AJAX requests, e.g. with some visual effect when the response comes. It sometimes happens that the user doesn't wait until the request is done (although he sees a loading indicator) and starts clicking other elements like crazy. Because in principle I cannot and don't want to disable that possibility, I have tried (more or less successfully) to ensure that anytime a new request is fired, the previous one is aborted (client-side) and its handlers are no longer called - whichever request comes last wins.I have been struggling with a situation on a si