AJAX异步无效

I try send 16 asynchronous request's to my back-end .

$.each(response, function( k, v ) {
    uploadAdditionalRows(v)
});

function uploadAdditionalRows(value) {
                $.ajax({
                    url: "/asins/table_data/" + encodeURIComponent(value),
                    cache:false,
                    type: "GET",
                    success: function(response) {
                        console.log(response);
                    }
                });

                return;
            }

But they return execute 1 after another.

How get response like this ? :

Browsers enforce a limit on the number of simultaneous HTTP connections they will open (and a smaller limit on the number of connections to any given domain).

If you exceed that limit, the requests enter a queue.

You can see this in that the first four start at the same time, then the rest are delayed.