Performing GET request before leaving page

If a GET request is made as follows

$(window).bind('beforeunload', function() {
    // GET request
});

and the page is abandoned before the GET request is completed,

will the destination server still process the request? Or will it somehow vanish?

I would like to send a server data on beforeunload firing, but without stealing useless ms from开发者_高级运维 the user.

It would be very useful if someone could help me.

If it is an asynchronous request then the server may process it (if it receives the request) but I don't know if you can guarantee that the request will go through before the page is unloaded or if it will be processed - this may depend on the actual web server (someone else may have more information). If you make a synchronous request, the page will wait until the request goes through and it gets back a response (so in this case, processing is guaranteed). However, this means that your browser will be locked up until that request completes, which may not be desirable.

In most cases yes, but it depends on the web application server. Some can detect the disconnect and stop with the request.