问题
My Co-worker told me that AJAX connection alive until a user closes his/her browser. As far as I know, ajax connection closes its connection when its request has completed. I tested it with Firebug and a HTTP monitoring tool, I noticed that AJAX connection closes itself.
Is he correct????
回答1:
Break down what AJAX is -- and XMLHttpRequest. It's a connection to a URI endpoint for some resource (image, text, whatever). Your browser closes the HTTP connection as soon as it's done.
回答2:
Ajax is just like any other request, when it completes the connection is closed. Your colleague is wrong.
Note : There are connection types that allow you to keep the connection open indefinitely
回答3:
Ajax connections closed after receiving data or if you close tab, then connections will force closed.
Here described Ajax life cycle.
回答4:
Late to the party here, but this regards an issue I'm actually dealing with right now...
I have a web server running on a severely resource constrained platform (128k Flash, 48k RAM) so it can only handle one connection at a time. Further connections are not handled until the current one is closed. Also, it does not force Connection: close on certain URLs because of a low latency requirement. In general, only one thing talks to the device at a time.
AJAX connections follow whatever rules the browser sets for other connections. In my case, I'm testing a web page that uses AJAX to read one of the keep-alive-allowed URLs once per second, and the browser does not close the connection until several seconds after the window is closed. As a result, other clients wait indefinitely.
So don't assume that XHR connections are closed when complete. They might not be; Firefox 21 sure isn't closing them.
My current problem is that I want to force my AJAX requests to close the socket on completion, and I'm using jQuery's .ajaxSend() pre-send hook to set the Connection: close header. The AJAX seems to be working, but when another client tries to connect, it gets "connection reset by peer", so I'm wondering if Firefox doesn't notice the "Connection: close" header on the XHR request and keeps its end of the socket open (until it times out after approximately three seconds) even after the server has closed its side.
回答5:
Using JQuery to make AJAX requests, some connections are maintained until the following AJAX call. This can become a real problem when the server holds streams open until the response's close event fires.
来源：https://stackoverflow.com/questions/5164081/does-ajax-connection-disconnect-at-some-point