Asynchronous Ajax Request Locking Browser

This is a simple snippet of code to launch an aynchronous ajax request. The processing time of the request is deliberately long (10 seconds or more). Why browser prevent my users

Solution 1:

PHP is the cause of the problem here. When you do session_start() the PHP locks the session file so there’s no concurrent writing to this file and gives the running script full access to the session variables ( reading and writing ).

So you need to call session_write_close() as soon as possible.