您可以轻松地异步执行此操作，而无需一次触发所有请求。您需要做的就是管理队列。为了清楚起见，以下是伪代码。它很容易转换为真实的AJAX请求：

// Basic structure of the request queue. It's a list of objects
// that defines ajax requests:
var request_queue = [{
    url : "some/path",
    callback : function_to_process_the_data
}];

// This function implements the main loop.
// It looks recursive but is not because each function
// call happens in an event handler:
function process_request_queue () {
    // If we have anything in the queue, do an ajax call.
    // Otherwise do nothing and let the loop end.
    if (request_queue.length) {
        // Get one request from the queue. We can either
        // shift or pop depending on weather you prefer
        // depth first or breadth first processing:
        var req = request_queue.pop();
        ajax(req.url,function(result){
            req.callback(result);
            // At the end of the ajax request process
            // the queue again:
            process_request_queue();
        }
    }
}

// Now get the ball rolling:
process_request_queue();

因此，基本上，我们将ajax调用本身转换为伪循环。基本上，这是递归完成的经典延续编程风格。

在您的情况下，请求的示例为：

request_queue.push({
    url : "path/to/OUTER/request",
    callback : function (result) {
        // You mentioned that the result of the OUTER request
        // should trigger another round of INNER requests.
        // To do this simply add the INNER requests to the queue:

        request_queue.push({
            url : result.inner_url,
            callback : function_to_handle_inner_request
        });
    }
});

这非常灵活，因为您不仅可以选择以广度优先还是深度优先（shift与pop）处理请求。但是，您也可以使用splice将内容添加到队列的中间，或者使用unshift
vs push将请求放置在队列的开头以处理高优先级的请求。

您还可以通过在每个循环中弹出多个请求来增加同时请求的数量。只需确保process_request_queue每个循环仅调用一次即可避免同时请求呈指数增长：

// Handling two simultaneous request channels:
function process_request_queue () {
    if (request_queue.length) {
        var req = request_queue.pop();
        ajax(req.url,function(result){
            req.callback(result);
            // Best to loop on the first request.
            // The second request below may never fire
            // if the queue runs out of requests.
            process_request_queue();
        }
    }
    if (request_queue.length) {
        var req = request_queue.pop();
        ajax(req.url,function(result){
            req.callback(result);
            // DON'T CALL process_request_queue here
            // We only want to call it once per "loop"
            // otherwise the "loop" would grow into a "tree"
        }
    }
}