You can use my service, http://ipinfo.io, for this. It will give you the client IP, hostname, geolocation information (city, region, country, area code, zip code etc) and network owner. Here’s a simple example that logs the city and country:
$.get("https://ipinfo.io", function(response) {
console.log(response.city, response.country);
}, "jsonp");
Here’s a more detailed JSFiddle example that also prints out the full response information, so you can see all of the available details: http://jsfiddle.net/zK5FN/2/
The location will generally be less accurate than the native geolocation details, but it doesn’t require any user permission.