How do you detect a website visitor's country (Specifically, US or not)?

Question

I need to show different links for US and non-US visitors to my site. This is for convenience only, so I am not looking for a super-high degree of accuracy, and security or

Answer 1

My solution, easy and small, in this example i test Canada region from language fr-CA or en-CA

if( preg_match( "/^[a-z]{2}\-(ca)/i", $_SERVER[ "HTTP_ACCEPT_LANGUAGE" ] ) ){

   $region = "Canada";

}