Why are blocked tabs to the same host, if one of the tabs a long running ajax request?

Is the chrome browser, which has two tabs, for example, let's call them "admin" and "site".
If on the tab "admin" click on the button that sends the ajax request and waits for a response (approximately 2 minutes), when you reboot the tab "site" it is not loaded until the ajax response on the tab "admin".
In firefox this behavior. There are suspicions that is associated with the http headers.
April 7th 20 at 15:39
2 answers
April 7th 20 at 15:41
Session are blocked by default, and while the first request is not completed access to the file of the sessions will not be the second request.

To requests immediately let go it is necessary to close session write via session_write_close();

And of course after that you cannot edit will be $_SESSION.
To begin working with the session it will be necessary again to do session_start();

// do something

And tabs will not be hanging.
De whole thing in session - rollin_Colli commented on April 7th 20 at 15:44
April 7th 20 at 15:43
The queue request processing on the server controls the output of the content only after completion of a previous request (for change, I suspect) to the application.
Perhaps due to the mechanism of open sessions.

Or set the restriction in settings on the web server: only one active connection with a single ip address.

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