jQuery Forum

Since $.ajax returns the xhr handle on async requests, you could have the root object check for an existing request and kill it via .abort() if it's not needed anymore (since the request has changed). Queueing up the requests is probably not what you want, but here's an untested implementation to get you started if it turns out you need it:

1. function ajaxQueueManager()
   {
       var queue = [], xhr = null;
       var start = function(item){
           xhr = $.ajax($.extend({
               complete: function(){
                   var item = queue.shift() || {};
                   if ( item.complete )
                       item.complete.apply(this, arguments);
                   xhr = null;
                   if ( queue.length )
                       start(queue[0]);
               }
           }, item));
       };
       this.ajax = function(item)
       {
           if ( queue.push(item) == 1 )
               start(item);
       };
       this.abort = function()
       {
           if ( xhr )
               xhr.abort();
2.         xhr = null;
           queue = [];
       };
   }
    ...
   var aqm = new ajaxQueueManager();
   aqm.ajax({
       url: "test.php?search=abc&type=2",
       cache: false
   });