免费提供根据查询的IP地址或者域名，查询该IP所属的区域，直接可以调用其API，用于自己的网站上做二次开发。
IP Geolocation API
Fast, accurate, reliable
Free for non-commercial use, no API key required
Easy to integrate, available in JSON, XML, CSV, Newline, PHP
Serving more than 1 billion requests per day, trusted by thousands of businesses