Ajax Post Request blocks website loading

I have a strange problem with using ajax post requests. I use the request to run an ImageMagick process directly on the command line by using php function exec(). The process takes about a minute, and then responds with some variables. This is working fine, except from one problem. During the execution time I cannot excess other parts of the website that are installed on the same webserver (as if the server is unreachable). When the process finis开发者_如何学Pythonhes, everything works fine again.

I first thought this to be due to an overloaded server. However, when you access the website via another browser, there are no problems, even during the execution time of the process in the other browser. So it looks like the problems has something to do with browsers blocking other requests during the post request.

Could anyone help me out here? What could be the root problem?

Found the solution! Thanks from the help by kukipei By adding session_write_close(); to the file of the ajax request (after is has read the userid and token), the session file is no longer locked, and all pages are accessible again. Problem was that the session was locked during the whole execution time of the process, which was not necessary, since I only needed the session to read the userid and token. So before calling the ImageMagick operation, I now add session_write_close()