JavaScript Date对象

<input type="button" value="倒计时" onClick="Btn_Click()" />


<div id='txt'></div>
<script>
var i=0;
var c = false
var d=0
var f =0
//--------------------------------------------------------------------------------
var date = new Date()         //获取当前时间
var old = date.getTime()      //获取开始时间
function timeHandle(){
date = new date()
console.log(date.getTime()-old)
}
//--------------------------------------------------------------------------------
function Btn_Click(){
if(c){
clearInterval(inttervalId)
}else{

date = new Date()                             //重新获取当前时间
old = date.getTime()
inttervalId = setInterval(countTime,1)        //重新获取开始时间
}
c=!c //取反
}
//--------------------------------------------------------------------------------
function countTime(){
date = new Date()
startTime1 = date.getTime()
var str = (startTime1 - old)
d = Math.floor(str/1000)
f = Math.floor(str%1000)
txt.innerHTML = d+":"+f
}
//-------------------------------------------------------------------------------
/*function inttervalhandle(){
  date = new Date()                   //重新获取当前时间戳
            appppp(date.getTime()-old) //传入一个当前时间减去开始时间的差值到函数中         
 }
 function appppp(a){
      var miao = Math.floor(a/1000)        //向下取整
      txt.innerHTML=(miao+':'+(a%1000))
 }*/
//-----------------------------------------------------------------------------
function intervalHandle(){
txt.innerHTML = i
i ++
}
</script>