console.log(Math.PI); //圆周率属性

     console.log(Math.max(9, 55, 88, 444)); //最大值属性

     console.log(Math.E); //欧拉常数

     console.log(Math.random()); //0到1之间的随机小数包括0 不包括1

     // 利用对象封装自己的数学对象  里面有π最大值和最小值

     var myMath = {

         PI: 3.141592653,

         max: function () {

             var max = arguments[0];

             for (let i = 0; i < arguments.length; i++) {

                 if (arguments[i] > max) {

                     max = arguments[i]

                 }

             }

             return max

         },

         min: function () {

             var min = arguments[0];

             for (let i = 0; i < arguments.length; i++) {

                 if (arguments[i] < min) {

                     min = arguments[i]

                 }

             }

             return min

         },

     }

     console.log(myMath.max(88, 7, 5, 99));

     // 得到两个数字之间的随机整数

     function getRandomInt(min, max) {

         return Math.floor(Math.random() * (max - min)) + min; //不含最大值，含最小值

     }

     var rf = getRandomInt(88, 444)

     console.log(rf);

     // 随机点名

     var nameArr = ['徐飞1', '徐飞2', '徐飞3', '徐飞4', '徐飞5']

     console.log(nameArr[getRandomInt(0, nameArr.length - 1)]);

     // 猜数字游戏

     var random = getRandomInt(1, 10)

     while (true) {

         var num = prompt("请输入1~10之间的数字")

         if (num > random) {

             alert("你猜大了")

         } else if (num < random) {

             alert("你猜小了")

         } else {

             alert("恭喜你,猜到了")

             break;

         }

     }

   var date2 = new Date('2012-12-12')

     console.log(date2);

     console.log(date2.getFullYear());

     console.log(date2.getMonth() + 1);

     console.log(date2.getDate());

     // 写一个2020年3月26日 星期四

     var date = new Date()

     var year = date.getFullYear();

     var month = date.getMonth() + 1;

     var dates = date.getDate();

     var day = date.getDay()

     var hours = date.getHours()

     var minutes = date.getMinutes()

     var seconds = date.getSeconds()

     var dateArr = ['星期日', '星期一', '星期二', '星期三', '星期四', '星期五', '星期六']

     console.log("今天是" + year + "年" + month + "月" + dates + "日" + hours + "点" + minutes + "分" + seconds + "秒" + "\t" +

         dateArr[day]);

     // 封装格式化日期

     function getTime() {

         var time = new Date();

         var y = time.getFullYear();

         var mh = time.getMonth() + 1;

         var dates = time.getDate();

         var day = time.getDay()

         var h = time.getHours();

         h = h < 10 ? '0' + h : h;

         var m = time.getMinutes();

         m = m < 10 ? '0' + m : m;

         var s = time.getSeconds();

         s = s < 10 ? '0' + s : s;

         return "现在是" + y + "年" + mh + "月" + dates + "号" + "\t" + h + ":" + m + ":" + s;

     }

     console.log(getTime());

     // 倒计时效果

     function conutDown(time) {

         var nowTime = +new Date()

         var inputTime = +new Date(time)

         var times = (inputTime - nowTime) / 1000; //剩余时间的秒数

         var d = parseInt(times / 60 / 60 / 24) //天

         d = d < 10 ? '0' + d : d;

         var h = parseInt(times / 60 / 60 % 24) //时

         h = h < 10 ? '0' + h : h;

         var m = parseInt(times / 60 % 60) //分

         m = m < 10 ? '0' + m : m;

         var s = parseInt(times % 60) //秒

         s = s < 10 ? '0' + s : s;

         return d + "天" + h + "时" + m + "分" + s + "秒"

     }

     console.log(conutDown('2020-3-27 18:00:00'));

     var date = new Date()

     console.log(date);