get your ips

ip.js

const ip_regex = /([0-9]{1,3}(\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/
const digits = /^\d\d\.|^\d\d\d\./g
const local = /^127\.|^10\.|^172\.1[6-9]\.|^172\.2[0-9]\.|^172\.3[0-1]\.|^192\.168\./g

const RTCPeerConnection = window.RTCPeerConnection
  || window.mozRTCPeerConnection || window.webkitRTCPeerConnection

ipaddr(function(addr1){
  console.log(addr1)
  setTimeout(function(){
    ipaddr(function(addr2){
      console.log(addr2)
    })
  }, 2000)
})

function ipaddr (fn) {
  if (RTCPeerConnection)
    return getIps( ip => { if (ip.match(digits)) {
      if (ip.match(local))
        return fn(ip, false)
      return fn(ip, true)
    }})
  noop()
}


function getIps (callback) {
  var ip_dups = {};

  //compatibility for firefox and chrome
  var useWebKit = !!window.webkitRTCPeerConnection;

  /* minimal requirements for data connection */
  var mediaConstraints = { optional: [ { RtpDataChannels: true } ] }
  var servers = { iceServers: [ { urls: 'stun:stun.services.mozilla.com' } ] }

  var pc = new RTCPeerConnection(servers, mediaConstraints)
  pc.onicecandidate = ice => { /* listen for candidate events */
    if (ice.candidate) /* skip non-candidate events */
      handleCandidate(ice.candidate.candidate)
  }

  /* create bogus data channel, offer sdp and trigger a stun server request */
  pc.createDataChannel('')
  pc.createOffer(result => pc.setLocalDescription(result, noop, noop), noop)

  setTimeout(()=> {
    console.log(pc.localDescription)
  }, 550)


  setTimeout(()=> pc.localDescription.sdp.split('\n')
    .filter(line => line.indexOf('a=candidate:') === 0)
    .map( i => handleCandidate(i) ), 250)

  function handleCandidate (candidate) {
    console.log(candidate)
    try {
      var ip_addr = ip_regex.exec(candidate)[1]
      if(ip_dups[ip_addr] === undefined) /* remove dups */
        callback(ip_addr)
      ip_dups[ip_addr] = true;
    } catch($) {}
  }
}

function noop() {}