JavaScript获取客户端IP地址

1. 第三方接口

1) 这里提供一个搜狐接口的地址：http://pv.sohu.com/cityjson?ie=utf-8 ，将这个js引入到页面即可得到returnCitySN。

2) api.ipify.org

https://api.ipify.org/?format=jsonp&callback=getIP

 <script type="application/javascript">
   function getIP(json) {
     document.write("My public IP address is: ", json.ip);
   }
 </script>

 <script type="application/javascript" src="https://api.ipify.org?format=jsonp&callback=getIP"></script>

或者

 $.getJSON('https://api.ipify.org?format=json', function(data){
     console.log(data.ip);
 });

2. 向服务器发送一个ajax请求，该请求包中会包含客户端的相关信息，当然也包括IP。

3. 使用webRTC，获取私有IP

The RTCPeerConnection() constructor returns a newly-created RTCPeerConnection, which represents a connection between the local device and a remote peer.（http://ourcodeworld.com/articles/read/257/how-to-get-the-client-ip-address-with-javascript-only）

 /**
  * Get the user IP throught the webkitRTCPeerConnection
  * @param onNewIP {Function} listener function to expose the IP locally
  * @return undefined
  */
 function getUserIP(onNewIP) { //  onNewIp - your listener function for new IPs
     //compatibility for firefox and chrome
     var myPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection;
     var pc = new myPeerConnection({
         iceServers: []
     }),
     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 iterateIP(ip) {
         if (!localIPs[ip]) onNewIP(ip);
         localIPs[ip] = true;
     }

      //create a bogus data channel
     pc.createDataChannel("");

     // create offer and set local description
     pc.createOffer().then(function(sdp) {
         sdp.sdp.split('\n').forEach(function(line) {
             if (line.indexOf('candidate') < 0) return;
             line.match(ipRegex).forEach(iterateIP);
         });

         pc.setLocalDescription(sdp, noop, noop);
     }).catch(function(reason) {
         // An error occurred, so handle the failure to connect
     });

     //listen for candidate events
     pc.onicecandidate = function(ice) {
         if (!ice || !ice.candidate || !ice.candidate.candidate || !ice.candidate.candidate.match(ipRegex)) return;
         ice.candidate.candidate.match(ipRegex).forEach(iterateIP);
     };
 }

 // Usage

 getUserIP(function(ip){
     alert("Got IP! :" + ip);
 });