web游览器的标签页仿 ios mac 苹果的墓碑机制 (js代码)

背景：

本来项目开发系统防挂机功能，在其余游览器中均可以使用。但是呢在苹果的safair游览器中会出现几率失效，最后经过排查发现是苹果的墓碑机制导致。即：此标签页活跃，其他标签页假死。然后就导致防挂机失效了。

原理：

假如当前游览器中有3个标签页分别是A,B,C，每个标签页都有倒计时。正常情况下，每个标签页都会倒计时。但是苹果游览器只会有一个标签页A正常倒计时，其余的B，C 倒计时不生效。

所以就需要仿墓碑机制进行开发。原理如下：

A标签页打开时，B和C标签页不活跃；

当打开其他标签页，ABC处于后台时候，最近操作的一个标签页处于活跃；

核心逻辑代码：

    //分钟数
         var min;
        var timeLeft;
        var timer=null;
        var IsnewRequest = false;
        var StayTimer = null;
        function resetTimer() {
            backInit();
        }

        function uuid(len, radix) {
            var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
            var uuid = [], i;
            radix = radix || chars.length;

            if (len) {
                // Compact form
                for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix];
            } else {
                // rfc4122, version 4 form
                var r;

                // rfc4122 requires these characters
                uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
                uuid[14] = '4';

                // Fill in random data.  At i==19 set the high bits of clock sequence as
                // per rfc4122, sec. 4.1.5
                for (i = 0; i < 36; i++) {
                if (!uuid[i]) {
                    r = 0 | Math.random()*16;
                    uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
                }
                }
            }

            return uuid.join('');
        }

        function GetBigTime() {

            //判断：如果有其他页面打开，则赋值最大倒计时值，如果< 10 退出
            //1,获取所有的time
            //2，取最大的时间
            //3，如果最大的时间<10 则不管；
            var countDownKeyList= [];
            var localStorageKeys = Object.keys(localStorage)
            for (var i=0;i<localStorageKeys.length;i++) {
                var item = localStorageKeys[i];
                if(item.indexOf("CountDown")!=-1)
                {
                countDownKeyList.push(item);
                }
            }

            var countDownValueList= [];
            for(var i= 0; i<countDownKeyList.length;i++)
            {
                var value = localStorage.getItem(countDownKeyList[i]);
                countDownValueList.push(value);
            }

            //验证最大时间
            var bigTime = countDownValueList.sort().reverse()[0];
            //if(Number(bigTime)>=3)
            if(Number(bigTime)>=3 && Number(bigTime) != 19999999)
            {
                //取运行中的倒计时最大值；
                window.localStorage.setItem(window.CountDown,bigTime);
                return false;
            }
            else
            {
                window.localStorage.removeItem(window.CountDown);
                return true;
            }

        }

        function  ShowCountDown (second){
            const s = second % 60;
            const m = Math.floor(second / 60);
            return `${`00${m}`.slice(-2)} : ${`00${s}`.slice(-2)}`;
        };  

        function reSetTimeoutInit()
        {
            window.localStorage.setItem("checkClose","1");
            setTimeout(function(){
            //1秒后执行刷新
            window.localStorage.removeItem('checkClose');
            }, 1000); //单位是毫秒
            setTimeoutInit();
        }

        var IsResetTime = false;
        function setTimeoutInit() {

            this.IsnewRequest = true;
            //默认无操作时间为15分钟
            min = 15;
            let value = window.localStorage.getItem("InvalidTime");
            //如果取不到session值 则默认15分钟
            if(value!=null && value!=undefined)
            {
                min =  Number(value);
            }            

            //清理之前的倒计时
            clearInterval(StayTimer);

            //没有唯一标识，则生成
            if(window.CountDown==''||window.CountDown==undefined)
            {
                window.CountDown = "CountDown"+this.uuid(8,2);
            }

            //设置初始倒计时
            var MainTime = min * 60;
            window.localStorage.setItem(window.CountDown,MainTime);     

            StayTimer = setInterval(()=>{

                var nowTime = window.localStorage.getItem(window.CountDown);
                if(nowTime==null||nowTime=="")
                {
                    clearInterval(StayTimer);
                    return;
                }
                //获取存储倒计时
                timeLeft = Number(nowTime);            

                var localStorageKeys = Object.keys(localStorage)
                var labelList =  localStorageKeys.filter(x=> x.indexOf("CountDown")!=-1 );
                var activeCount = 0;
                for(var i= 0; i<labelList.length;i++)
                {
                    var value = localStorage.getItem(labelList[i]);
                    var nValue =  Number.parseInt(value);
                    if(nValue!=19999999)
                    {
                    activeCount++;
                    }
                }      

                var localStorageKeys = Object.keys(localStorage)
                var labelList =  localStorageKeys.filter(x=> x.indexOf("CountDown")!=-1 );
                var activeCount = 0;
                for(var i= 0; i<labelList.length;i++)
                {
                    var value = localStorage.getItem(labelList[i]);
                    var nValue =  Number.parseInt(value);
                    if(nValue!=19999999)
                    {
                    activeCount++;
                    }
                }
                //如果没有一个活跃，则重新读取
                if(activeCount==0)
                {
                    this.IsnewRequest = true;
                }

                if(this.IsnewRequest==true)
                {
                    this.IsnewRequest = false;
                    for(var i= 0; i<labelList.length;i++)
                    {
                    if(labelList[i]!=window.CountDown)
                    {
                        var value = localStorage.getItem(labelList[i])
                        localStorage.setItem(labelList[i],"19999999");
                    }
                    else
                    {
                        timeLeft = MainTime;//设置的默认值
                        localStorage.setItem(labelList[i],MainTime);
                    }
                    }
                }      

                if (document.hidden) {
                    //首先重置时间
                    //赋值其余的为-999
                    if(timeLeft==19999999)
                    {
                    IsResetTime = true
                    const show = ShowCountDown(timeLeft);//恢复倒计时 并且重置时间；
                    console.log("[时停],倒计时："+timeLeft);
                    }
                    else
                    {
                    if(IsResetTime)
                    {
                        timeLeft = MainTime;//设置的默认值
                        IsResetTime = false;
                    }
                    const show = ShowCountDown(timeLeft--);//恢复倒计时 并且重置时间；
                    console.log("[独苗],倒计时："+timeLeft);
                    }
                } else {
                    //首先重置时间
                    //赋值其余的为-999
                    if(timeLeft==19999999)
                    {
                    IsResetTime = true
                    const show = ShowCountDown(timeLeft);//恢复倒计时 并且重置时间；
                    console.log("[时停],倒计时："+timeLeft);
                    }
                    else
                    {
                    if(IsResetTime)
                    {
                        timeLeft = MainTime;//设置的默认值
                        IsResetTime = false;
                    }
                    const show = ShowCountDown(timeLeft--);//恢复倒计时 并且重置时间；
                    console.log("[独苗],倒计时："+timeLeft);
                    }
                }      

                var checkShow = window.localStorage.getItem('checkShow');
                var blCheckShow =Number(checkShow);
                if(blCheckShow==1)
                {
                    timeLeft = -1;
                    setTimeout(function(){
                    //1秒后执行刷新
                    window.localStorage.removeItem('checkShow');
                    }, 1000); //单位是毫秒
                }

                //const show = ShowCountDown(timeLeft--);
                //设置倒计时
                window.localStorage.setItem(window.CountDown,timeLeft);
                if (timeLeft < 0)
                {
                    //#endregion
                    window.localStorage.setItem('checkShow',"1");
                    var IsResetTime = false;
                    var blresult = this.GetBigTime();
                    if(blresult==true)
                    {
                        //清理定时
                        clearInterval(StayTimer);
                        //业务操作：
                        document.getElementsByClassName("fullScreenDiv")[0].style.display = "block";
                        document.getElementsByClassName("promptDiv")[0].style.display = "block";
                        startCountDown($("#spanCountDown").text()); 

                    }

                }                    

            },1000);

            //countTime();

            var vdoc = document.getElementById("ScormIframe").contentDocument;

            if (vdoc != null) {
                vdoc.addEventListener("mousemove", resetTimer, false);
                vdoc.addEventListener("mousedown", resetTimer, false);
                vdoc.addEventListener("keypress", resetTimer, false);
                vdoc.addEventListener("DOMMouseScroll", resetTimer, false);
                vdoc.addEventListener("mousewheel", resetTimer, false);
                vdoc.addEventListener("touchmove", resetTimer, false);
                vdoc.addEventListener("MSPointerMove", resetTimer, false);
            }
            else{
            }

            if (language == "zh-CN") {
                        $("#msgInfo").html("由于长时间未操作，课件将在倒计时结束后自动关闭，系统会保存您的学习记录。");
                        $("#msgTimeout").html("如果您想继续学习，请关闭此窗口。");
                    }
                    else {
                        $("#msgInfo").html("Since there is no operation for a period of time, the courseware will be closed automatically at the end of the countdown and the learning record will be saved.");
                        $("#msgTimeout").html("If you want to continue learning, just close this window.");
                    }
        } 

        function countTime() {
                if (timeLeft == 0) {
                    document.getElementsByClassName("fullScreenDiv")[0].style.display = "block";
                    document.getElementsByClassName("promptDiv")[0].style.display = "block";
                    startCountDown($("#spanCountDown").text());
                }

                var startMinutes = parseInt(timeLeft / (60 * 1000), 10);
                var startSec = parseInt((timeLeft - startMinutes * 60 * 1000) / 1000)
                timeLeft = timeLeft - 1000;
                setTimeout('countTime()', 1000);
                //console.log(timeLeft);
            }

            function startCountDown(html){
                clearInterval(this.CountDownTimer);
                        this.CountDownTimer = setInterval(() => {

                            var checkClose = window.localStorage.getItem('checkClose');
                            var blCheckClose =Number(checkClose);
                            if(blCheckClose==1)
                            {
                                // $("#spanCountDown").text(60);
                                // clearInterval(this.CountDownTimer);
                                document.getElementsByClassName("fullScreenDiv")[0].style.display = "none";
                                document.getElementsByClassName("promptDiv")[0].style.display = "none";
                                setTimeoutInit();
                                setTimeout(function(){
                                //1秒后执行刷新
                                window.localStorage.removeItem('checkClose');
                                }, 1000); //单位是毫秒
                            }
                            else
                            {
                                html = parseInt(html) - 1;
                                if (parseInt(html) <= 0) {
                                    closeme();
                                }
                                $("#spanCountDown").text(html);
                            }
                            ////console.log($("#spanCountDown").text());
                        }, 1000);
            }
        function closeme() {
            var browserName = navigator.appName;
            if (browserName == "Netscape") {
                window.open('', '_parent', '');
                window.close();
            } else if (browserName == "Microsoft Internet Explorer") {
                window.opener = "whocares";
                window.close();
            }
        }

        function backInit() {

                reSetTimeoutInit();                

                // min = 15;
                // timeLeft = min * 60 * 1000;
                $("#spanCountDown").text(60);
                clearInterval(this.CountDownTimer);
                document.getElementsByClassName("fullScreenDiv")[0].style.display = "none";
                document.getElementsByClassName("promptDiv")[0].style.display = "none";
            }

结语：

其实就是按照墓碑机制进行仿照开发，此文章进行记录以后可以在其他平台进行此机制的开发；