IP to Location using Javascript

A free open source community run geolocation ip service that runs on the MaxMind database is available here: https://ipstack.com/

Example

https://api.ipstack.com/160.39.144.19

Limitation

10,000 queries per month

It's quite easy with an API that maps IP address to location. Run the snippet to get city & country for the IP in the input box.

$('.send').on('click', function(){

  $.getJSON('https://ipapi.co/'+$('.ip').val()+'/json', function(data){
      $('.city').text(data.city);
      $('.country').text(data.country);
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input class="ip" value="8.8.8.8">
<button class="send">Go</button>
<br><br>
<span class="city"></span>, 
<span class="country"></span>

You can submit the IP you receive to an online geolocation service, such as http://www.geoplugin.net/json.gp?ip=<your ip here>&jsoncallback=<suitable javascript function in your source>, then including the source it returns which will run the function you specify in jsoncallback with the geolocation information.

Alternatively, you may want to look into HTML5's geolocation features -- you can see a demo of it in action here. The advantage of this is that you do not need to make requests to foreign servers, but it may not work on browsers that do not support HTML5.