How do I retrieve the visitor's ISP through PHP?

Question

How do I find out the ISP provider of a person viewing a PHP page?

Is it possible to use PHP to track or reveal it?

If I use something like the following:

Answer 1

If all these answers are not useful then you can try API way.

1.http://extreme-ip-lookup.com/json/[IP ADDRESS HERE]

EXAMPLE: http://extreme-ip-lookup.com/json/106.192.146.13

2.http://ip-api.com/json/[IP ADDRESS HERE]

EXAMPLE: http://ip-api.com/json/113.14.168.85

once it works for you don't forget to convert JSON into PHP.