JavaScript 学习笔记— —Date对象

一、获取时间

function toTwo(n){
      return n<10 ? '0'+n :''+n;
  }
  function getTime(){
      var objDate=new Date(); //date=>object
      //number
      var year=objDate.getFullYear();
      var mothn=objDate.getMonth();
      var date=objDate.getDate();
      var week=objDate.getDay();
      var hours=objDate.getHours();
      var minu=objDate.getMinutes();
      var sec=objDate.getSeconds();
      mothn=mothn+1;
      switch (week)
      {
          case 0:
              week="星期天"
          case 1:
              week="星期一"
          case 2:
              week="星期二"
          case 3:
              week="星期三"
          case 4:
              week="星期四"
          case 5:
              week="星期五"
          case 6:
              week="星期六"
      }
      var str=year+"年"+mothn+"月"+date+"日 "+week+" "+toTwo(hours)+"时"+toTwo(minu)+"分"+toTwo(sec)+"秒";
      document.body.innerHTML=str;
  }
  setInterval(getTime,1000);
  getTime();

二、倒计时

function timeDown()
    {
        var timer=null;
        //new Date(2015, 3, 6, 0, 0, 0) 月份从0开始，即3表示4月份

        var iNow=new Date();
        var iNew=new Date(2015, 3, 5, 22, 23,0);

        var ts = iNew-iNow;
        var dd = parseInt(ts / 1000 / 60 / 60 / 24, 10);
        var hh = parseInt(ts / 1000 / 60 / 60 % 24, 10);
        var mm = parseInt(ts / 1000 / 60 % 60, 10);
        var ss = parseInt(ts / 1000 % 60, 10);
        dd = checkTime(dd);
        hh = checkTime(hh);
        mm = checkTime(mm);
        ss = checkTime(ss);
        var str= dd + "天" + hh + "时" + mm + "分" + ss + "秒";
        document.body.innerHTML=str;
        if(iNow.toString()==iNew.toString()) {
           clearInterval(timer);
        }
    }
    function checkTime(n){
        return n<10 ? '0'+n :''+n;
    }
    var timer=setInterval(timeDown,1000);
    timeDown();