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 spoofing are not a concern.

I know there are geotargeting services and lists, but this seems like overkill since I only need to determine (roughly) if the person is in the US or not.

I was thinking about using JavaScript to get the user's timezone, but this appears to only give the offset, so users in Canada, Mexico, and South America would have the same value as people in the US.

Are there any other bits of information available either in JavaScript, or PHP, short of grabbing the IP address and doing a lookup, to determine this?

Answer 1

The best indicator is probably the HTTP Accept-Language header. It will look something like below in the HTTP request:

GET / HTTP/1.1
Accept: */*
Accept-Language: en-us
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.21022; .NET CLR 3.5.30729; MDDC; OfficeLiveConnector.1.4; OfficeLivePatch.0.0; .NET CLR 3.0.30729)
Accept-Encoding: gzip, deflate
Host: www.google.com
Connection: Keep-Alive

You should be able to retrieve this in PHP using the following:

<?php
echo $_SERVER['HTTP_ACCEPT_LANGUAGE'];
?>

Answer 2

There are some free services out there that let you make country and ip-based geolocalization from the client-side.

I've used the wipmania free JSONP service, it's really simple to use:

<script type="text/javascript">
  // plain JavaScript example
  function jsonpCallback(data) { 
    alert('Latitude: ' + data.latitude + 
          '\nLongitude: ' + data.longitude + 
          '\nCountry: ' + data.address.country); 
  }
</script>
<script src="http://api.wipmania.com/jsonp?callback=jsonpCallback"
        type="text/javascript"></script>

Or if you use a framework that supports JSONP, like jQuery you can:

// jQuery example
$.getJSON('http://api.wipmania.com/jsonp?callback=?', function (data) { 
  alert('Latitude: ' + data.latitude + 
        '\nLongitude: ' + data.longitude + 
        '\nCountry: ' + data.address.country); 
});

Check the above snippet running here.

Answer 3

I would say that geotargetting is the only method that's even remotely reliable. But there are also cases where it doesn't help at all. I keep getting to sites that think I'm in France because my company's backbone is there and all Internet traffic goes through it.

The HTTP Accept Header is not enough to determine the user locale. It only tells you what the user selected as their language, which may have nothing to do with where they are. More on this here.

Answer 4

@CMS

How could your code be modified so that instead of an alert dialog there is URL redirect that takes a US visitor to a .COM address & allows a Canadian visitor passes through normally?

(For a .CA version of a website with a sister .COM version site)

Answer 5

Depending on which countries you want to distinguish, time zones can be a very easy way to achieve it - and I assume it's quite reliable as most people will have the clocks on their computers set right. (Though of course there are many countries you can't distinguish using this technique).

Here's a really simple example of how to do it:

http://unmissabletokyo.com/country-detector