Capturing visitor's IP in javascript?

I am trying to use json to caputure visitor's IP address

$.getJSON("http://jsonip.appspot.com?callback=?",
    function(data){
window.alert(data.ip);
  });

Code (markup):

The above code displays the IP address in alert box.
However I want to capture the result in a javascript variable

$.getJSON("http://jsonip.appspot.com?callback=?",
    function(data){
var ip = data.ip;
  });

Code (markup):

but that doesn't work. Really need some help on how to capture the json results in a custom javascript variable

 

It should work just fine. Perhaps you should change the scope of your variable.

var ip;
$.getJSON("http://jsonip.appspot.com?callback=?",
    function(data){
ip = data.ip;
alert("My ip is " + ip);
  });

Code (markup):