如果 Javascript 不是多线程的，是否有任何理由实现异步 Ajax Queuing?

I am having issues with my php server (my computer is the only connection). I initially thought part of the reason was because of too many ajax requests (I have a script that executes an ajax request per keystroke) so I implemented a design to control the flow of ajax requests into a queue. Below is my code:

//global vars:
activeAjaxThread = 0; //var describing ajax thread state
ajaxQue = [];  //array of ajax request objects in queue to be fired after the completion of the previous request

function queRequest(ajaxObj) {
  ajaxQue.push(ajaxObj);
  if (activeAjaxThread == 0) {
    fireOffAjaxQue();   
  } else {
    return 'ajax thread is running';
  }
}

function fireOffAjaxQue () {
  activeAjaxThread = 1;
  //getLastRequest();
  if ((ajaxQue.length > 0) && activeAjaxThread == 1) {
    $.ajax(ajaxQue[0]).always( function () {
      ajaxQue.shift(); 
      if (ajaxQue.length > 0) {
        fireOffAjaxQue();   //fire off another ajax request since this one has been completed. 
      }
    });
  }
  activeAjaxThread = 0;   //thread has finished executing
}

实施:

//create ajax object
var ajaxObj = {
  url: 'someplace.php',
  data: dataVar,
  success: function (data) {...}
};
//send ajax object to que
queRequest(ajaxObj);

然后我发现 Javascript 是多线程的，并阅读了一些关于 Javascript 事件处理的文章，例如 http://ejohn.org/blog/how-javascript-timers-work/ 作者:John Resig(jQuery extra-ordinaire)