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A countdown class implemented in JavaScript_javascript skills

WBOYOriginal: 2016-05-16 16:09:53961browse

Recently I am working on a lottery project of Rank 5. Each issue has a lottery purchase period. That is, when the user opens the page of Rank 5, a remaintime (the remaining time until the end of this lottery period) will be transmitted from the server. Then this time is decremented and presented to the user on the client, allowing the user to obtain the remaining time of this lottery period.

The implementation principle is quite simple, so I won’t go into details here. Run the following code to view the demo:

<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>index</title>
<style type="text/css">
em{color:#f00;}
</style>
</head>

<body>
<div id="remaintime"></div>
<script type="text/javascript">

var TheTime = function(){
 this.init.apply(this,arguments);
};

TheTime.prototype = {
 init: function(obj){
 var that = this;
 obj = that.buildParam(obj);
 that.callback = obj.callback;
 var container = that.container = document.getElementById(obj.container);
 container.innerHTML = '<em></em>小时<em></em>分钟<em></em>秒';
 var hourSpace = that.hourSpace = container.getElementsByTagName('em')[0];
 var minuteSpace = that.minuteSpace = container.getElementsByTagName('em')[1];
 var secondSpace = that.secondSpace = container.getElementsByTagName('em')[2];
 if(obj.remaintime==0){
  that.resetTime();
  return;
 }

 that.hours = Math.floor(obj.remaintime/3600);
 that._remainder1 = obj.remaintime % 3600;
 that.minutes = Math.floor(that._remainder1/60);
 that.seconds = that._remainder1 % 60;
 var timer = that.timer = setInterval(function(){
  that.renderTime.apply(that);
 },1000);
 },
 buildParam: function(obj){
 obj = {
  //container为dom节点的id
  container: obj.container || 'container',
  remaintime: Number(obj.remaintime) || 0,
  //倒计时完成后的回调
  callback: obj.callback || new Function
 };
 return obj;
 },
 resetTime: function(){
 var that = this;
 that.container.innerHTML = "已经截止";
 },
 //刷新时间
 renderTime: function(){
 //debugger;
 var that = this;
 if(that.seconds>0){
  that.seconds--;
 }else{
  that.seconds = 59;
  if(that.minutes>0){
  that.minutes--;
  }else{
  that.minutes = 59;
  if(that.hours>0){
   that.hours--;
  }
  }
 }
 
 //时刻监听
 if(that.hours==0 && that.minutes==0 && that.seconds==0){
  //执行回调
  that._callback();
 }
 var bitHandle = that.bitHandle;

 var _hour = bitHandle(that.hours);
 var _minute = bitHandle(that.minutes);
 var _second = bitHandle(that.seconds);
 that.hourSpace.innerHTML = _hour;
 that.minuteSpace.innerHTML = _minute;
 that.secondSpace.innerHTML = _second;
 },
 //对于位数的处理，确保返回两位数
 bitHandle: function(num){
 var str = num.toString();
 if(str.length<2){
  str = 0 + str;
 }
 return str;
 },
 _callback: function(){
 var that = this;
 clearInterval(that.timer);
 that.callback();
 }

};

new TheTime({
 //容器id
 container: 'remaintime',
 //服务器返回的剩余时间，单位为秒
 remaintime: 10000,
 //倒计时完成时的回调
 callback: function(){
 document.getElementById('remaintime').innerHTML = '已截止';
 }
});
</script>
</body>
</html>

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