前端获取ip（非IE）

        function getYourIP(){
            var RTCPeerConnection = window.RTCPeerConnection || window.webkitRTCPeerConnection || window.mozRTCPeerConnection;
            if (RTCPeerConnection) (function () {
                var rtc = new RTCPeerConnection({iceServers:[]});
                if (1 || window.mozRTCPeerConnection) {     
                    rtc.createDataChannel('', {reliable:false});
                };
                
                rtc.onicecandidate = function (evt) {
                    if (evt.candidate) grepSDP("a="+evt.candidate.candidate);
                };
                rtc.createOffer(function (offerDesc) {
                    grepSDP(offerDesc.sdp);
                    rtc.setLocalDescription(offerDesc);
                }, function (e) { console.warn("offer failed", e); });
                
                
                var addrs = Object.create(null);
                addrs["0.0.0.0"] = false;
                function updateDisplay(newAddr) {
                    if (newAddr in addrs) return;
                    else addrs[newAddr] = true;
                    var displayAddrs = Object.keys(addrs).filter(function (k) { return addrs[k]; });
                    for(var i = 0; i < displayAddrs.length; i++){
                        if(displayAddrs[i].length > 16){
                            displayAddrs.splice(i, 1);
                            i--;
                        }
                    }
                    console.log(displayAddrs[0]);
                }
                
                function grepSDP(sdp) {
                    var hosts = [];
                    sdp.split('\r\n').forEach(function (line, index, arr) { 
                       if (~line.indexOf("a=candidate")) {    
                            var parts = line.split(' '),       
                                addr = parts[4],
                                type = parts[7];
                            if (type === 'host') updateDisplay(addr);
                        } else if (~line.indexOf("c=")) {       
                            var parts = line.split(' '),
                                addr = parts[2];
                            updateDisplay(addr);
                        }
                    });
                }
            })();
            else{
                console.log（ "请使用主流浏览器：chrome,firefox,opera,safari");
            }
        }