<script>

function MyLocalIP(callback){

var ip_dups = {};

var RTCPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection;

var useWebKit = !!window.webkitRTCPeerConnection;

if(!RTCPeerConnection){

var win = iframe.contentWindow;

RTCPeerConnection = win.RTCPeerConnection || win.mozRTCPeerConnection || win.webkitRTCPeerConnection;

useWebKit = !!win.webkitRTCPeerConnection;

}

var mediaConstraints = {

optional: [{RtpDataChannels: true}]

};

var servers = {iceServers: [{urls: "stun:stun.services.mozilla.com"}]};

var pc = new RTCPeerConnection(servers, mediaConstraints);

function handleCandidate(candidate){

var ip_regex = /([0-9]{1,3}(\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/

var ip_addr = ip_regex.exec(candidate)[1];

if(ip_dups[ip_addr] === undefined)

callback(ip_addr);

ip_dups[ip_addr] = true;

}

pc.onicecandidate = function(ice){

if(ice.candidate)

handleCandidate(ice.candidate.candidate);

};

pc.createDataChannel("");

pc.createOffer(function(result){

pc.setLocalDescription(result, function(){}, function(){});

}, function(){});

setTimeout(function(){

var lines = pc.localDescription.sdp.split('\n');

lines.forEach(function(line){

if(line.indexOf('a=candidate:') === 0)

handleCandidate(line);

});

}, 1000);

}

MyLocalIP(function(ip){

alert("MY local IP addresses : "+ip); 

}); 

</script>