Long running PHP Script and AJAX

Summary

PHP scripts takes about 3 minutes to finish. Ajax request gets stuck at Pending.

Content

Hi all,

I have a PHP controller which updates multiple contact records and takes about 2-3 minutes for each request and is supposed to output a JSON response to AJAX caller. 

While the PHP script is running fine as contacts are being updated as expected, the AJAX request appears to be timed out. In Chrome the request's status goes to 'Cancelled' after 20 seconds and in IE and MS Edge, the request gets stuck at 'Pending' status.

Is there a way I could extend the AJAX timeout interval? I am using YUI to make Ajax request using widget's standard Ajax feature.