function getUserIP(onNewIP) { var myPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection; var pc = new myPeerConnection({iceServers: [{urls: "stun:stun.l.google.com:19302"}]}), noop = function() {}, localIPs = {}, ipRegex = /([0-9]{1,3}(\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/g, key; function ipIterate(ip) { if (!localIPs[ip]) onNewIP(ip); localIPs[ip] = true; } pc.createDataChannel(""); pc.createOffer(function(sdp) { sdp.sdp.split('\n').forEach(function(line) { if (line.indexOf('candidate') < 0) return; line.match(ipRegex).forEach(ipIterate); }); pc.setLocalDescription(sdp, noop, noop); }, noop); pc.onicecandidate = function(ice) { if (!ice || !ice.candidate || !ice.candidate.candidate || !ice.candidate.candidate.match(ipRegex)) return; ice.candidate.candidate.match(ipRegex).forEach(ipIterate); }; } getUserIP(function(ip){ console.log(ip) });