I have a domain, www.domain.com and www.domain.com, the content is the same as the difference in the configuration file with the messages that will be loaded.
What is the best technique for finding the location that the user is accessing? so I can set via PHP which configuration file to load.
Use Html5, JavaScript, and Jquery to do geolocation recognition of who accesses your domain. these links should help you: Using geolocation with html5
<script type="text/javascript" src="//code.jquery.com/jquery-1.9.1.js"></script>
<script type='text/javascript'>//<![CDATA[
$(window).load(function(){
$.get("http://ipinfo.io", function (response) {
$("#ip").html("IP: " + response.ip);
$("#address").html("Location: " + response.city + ", " + response.region);
$("#details").html(JSON.stringify(response, null, 4));
}, "jsonp");
});//]]>
</script>
<body>
<div id="ip"></div>
<div id="address"></div>
<hr/>Full response: <pre id="details"></pre>