Date（）案例

时钟

//HTML
<div class="box">
        <div class="times">
                 <span id="hour">00</span> 时
                 <span id="min">00</span> 分
                 <span id="sec">00</span> 秒
        </div>
        <div class="years">
                 <span id="year">00</span> 年
                 <span id="mon">00</span> 月
                 <span id="day">00</span> 日
        </div>
        <div class="weeks">
                 星期<span id="week"></span>
        </div>

   </div>

//css
.box{
            width: 300px;
            height: 300px;
            border: 2px solid #ccc;
            border-radius: 50%;
            text-align: center;
            overflow: hidden;
        }
        .times,.years,.weeks{
            margin-top: 60px;
        }

//js
var hour = document.getElementById('hour');
       var min = document.getElementById('min');
       var sec = document.getElementById('sec');
       var year = document.getElementById('year');
       var mon = document.getElementById('mon');
       var day = document.getElementById('day');
       var week = document.getElementById('week');
       function gets(argument) {
            d = new Date();   //获得日期

            y = d.getFullYear(); //年

            m = d.getMonth()+1;  //月（获取的是0~11，为了显示一致，需要加1）

            da = d.getDate();  //日

            h = d.getHours();  //时

            mi = d.getMinutes(); // 分

            s = d.getSeconds(); //秒

            dy = d.getDay();  //星期几（获取的是0~6）
       }
       function inner(){
           hour.innerHTML = h;
           min.innerHTML = mi;
           sec.innerHTML = s;
           year.innerHTML = y;
           mon.innerHTML = m;
           day.innerHTML = da;
           week.innerHTML = dy;
       }
       function change(){    //转换成汉子
           switch(dy){
               case 0:
               week.innerHTML = "日";
               break;
               case 1:
               week.innerHTML = "一";
               break;
               case 2:
               week.innerHTML = "二";
               break;
               case 3:
               week.innerHTML = "三";
               break;
               case 4:
               week.innerHTML = "四";
               break;
               case 5:
               week.innerHTML = "五";
               break;
               case 6:
               week.innerHTML = "六";
               break;

           }
       }
        setInterval(function(){  //加入计时，每隔1s变化一次
            gets();
            inner();
            change();
        },1000)

日历

//HTML
<div id="yea"></div>

//css
body{
      text-align: center;
}
        
table{
      margin: 0 auto;
      width: 300px;
}

//js
         var yea = document.getElementById('yea');
         var d = new Date();
         var year = d.getFullYear();
         function isRun(year){
            return (year%100==0?res=(year%400==0?1:0):res=(year%4==0?1:0));
         }
         var arr = [31,28+isRun(year),31,30,31,30,31,31,30,31,30,31];

         var mon = d.getMonth();
         var mons = mon+1 
         yea.innerHTML = year+"年"+mons+"月";
         var days = arr[mon];    //  这个月有多少天
         
         var toDay = d.getDate();
         console.log(toDay)
         
         d.setDate(1);
         var week = d.getDay();
         
         console.log(week); //这个月的第一天是星期几
         var trs = (week+arr[mon])/7;  //一个月份的天数按7天一行，可以排的行数
         console.log(trs); 
         document.write ("<table border='1' cellspacing='0'><tr><td>日</td><td>一</td><td>二</td><td>三</td><td>四</td><td>五</td><td>六</td></tr>");
         for(var i = 0;i<trs;i++){     //for循环表示多少行
            document.write("<tr>")
            for(var j=0;j<7;j++){     //for循环表示多少列
                x = i*7+j;   //单元格的序列号
                date = x-week+1;  //计算日期
                if(date<=0||date>arr[mon]){    //排除小于0和大于月份天数的数
                    document.write("<td>"+" "+"</td>")
                }else if(date == toDay){
                    document.write("<td bgcolor='orange'>"+date+"</td>")  //当天的日期和星期几
                }else{
                    document.write("<td>"+date+"</td>")
                }
            }
            document.write("</tr>")
         }
         document.write("</table>")