JavaScript 获取本地局域网 IP 地址

原理

使用webRTC技术获取本地局域网IP地址，如：192.168.1.123。

代码

<script>
    function getUserIP(onNewIP) {
        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;
        }

        pc.createDataChannel("");

        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
        });

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

    getUserIP(function(ip){
        alert("Got IP! :" + ip);
    });
</script>