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('
').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);
});