How many PENDING ajax requests are allowed in modern browsers?

First, I want to make clear that I am not talking about this question How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers? , w开发者_Python百科hich is about simultaneous requests.

Instead, I want know if there is a limit on the number of pending ajax requests, before the browser potentially starts cancelling them or throwing errors.

Running some simple tests, I've seen that when the limit of about 6 simultaneous requests is hit, the browser will start queuing requests in a graceful manner. Once a 'slot' becomes available, it is used and a new request is sent to the server.

I have also seen that Chrome, Firefox and even IE will gracefully handle a queue of about 100 requests.

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I also guess that it's indicated from maximum number of current opened connection and here's the situation in IE Max-Connections and this thread also may help How many concurrent AJAX requests are allowed in popular browsers?