How to perform Ajax requests, a few at a time

Question

I am not really sure it is possible in JavaScript, so I thought I\'d ask. :)

Say we have 100 requests to be done and want to speed things up.

What I was thin

Answer 1

It's actually slower to break up 100 requests and batch post them 5 at a time whilst waiting for them to complete till you send the next batch. You might be better off simply sending 100 requests, remember JavaScript is single threaded so it can only resolve 1 response at a time anyways.

A better way is set up a batch request service that accepts something like:

/ajax_batch?req1=/some/request.json&req2=/other/request.json

And so on. Basically you send multiple requests in a single HTTP request. The response of such a request would look like:

[
   {"reqName":"req1","data":{}},
   {"reqName":"req2","data":{}}
]

Your ajax_batch service would resolve each request and send back the results in proper order. Client side, you keep track of what you sent and what you expect, so you can match up the results to the correct requests. Downside, it takes quite some coding.

The speed gain would come entirely from a massive reduction of HTTP requests. There's a limit on how many requests you send because the url length has a limit iirc.

DWR does exactly that afaik.