JavaScript使用setTimeout實現(xiàn)倒計時效果

更新時間：2021年02月19日 10:27:50 作者：清水拌墨茶

這篇文章主要為大家詳細介紹了JavaScript使用setTimeout實現(xiàn)倒計時效果，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

為了加強對JavaScript原生代碼的編寫能力，以及鞏固setTimeout()的使用方法，制作了一個倒計時的demo，倒計時在現(xiàn)在的網(wǎng)站中算是一個常見的小功能，如果大家喜歡的話可以留下，就當作一個日常實用的小腳本。

實現(xiàn)思路

1、先獲取小時值將小時值減1開始進行倒計時分鐘59 秒數(shù)59
2、秒數(shù)的個位從9開始遞減，當秒數(shù)個位小于0時，秒數(shù)的十位減1
3、秒數(shù)的十位小于0時，分鐘的個位減1
4、分鐘的個位小于0時，分鐘的十位減1
5、分鐘的十位小于0時，小時減1
6、小時數(shù)小于0后停止計時全部為0

實現(xiàn)代碼

html

<p>倒計時：</p>
<span id="hour">5</span>
<span>:</span>
<span id="minuteTen">0</span>
<span id="minuteBit">0</span>
<span>:</span>
<span id="secondTen">0</span>
<span id="secondBit">0</span>

css

span{
 display: inline-block;
 width: 20px;
 height: 20px;
 background-color: #000000;
 color: #ffffff;
 text-align: center;
 }

JavaScript

 function time(){
 /*小時*/
 var hourTxt = document.getElementById("hour");
 var hour = parseInt(document.getElementById("hour").innerHTML);
 /*分鐘*/
 var minuteTenTxt = document.getElementById("minuteTen");
 var minuteBitTxt = document.getElementById("minuteBit");
 var minuteTen = parseInt(document.getElementById("minuteTen").innerHTML);
 var minuteBit = parseInt(document.getElementById("minuteBit").innerHTML);
 /*秒*/
 var secondTenTxt = document.getElementById("secondTen");
 var secondBitTxt = document.getElementById("secondBit");
 var secondTen = parseInt(document.getElementById("secondTen").innerHTML);
 var secondBit = parseInt(document.getElementById("secondBit").innerHTML);
 function start(){
 hour--;
 hourTxt.innerHTML = hour;
 minuteTen = 5;
 minuteTenTxt.innerHTML = minuteTen;
 minuteBit = 9;
 minuteBitTxt.innerHTML = minuteBit;
 secondTen = 5;
 secondTenTxt.innerHTML = secondTen;
 secondBit = 9;
 secondBitTxt.innerHTML = secondBit;

 /*secondBit開始自減*/
 function second(){
  secondBit--;
  secondBitTxt.innerHTML = secondBit;

  /*十秒過后*/
  if(secondBit < 0){
  secondTen--;
  secondTenTxt.innerHTML = secondTen;
  secondBit = 9;
  secondBitTxt.innerHTML = secondBit;
  /*繼續(xù)倒計時*/
  setTimeout(second,1000);

  /*一分鐘過后*/
  if(secondTen < 0){
   minuteBit--;
   minuteBitTxt.innerHTML = minuteBit;
   secondTen = 5;
   secondTenTxt.innerHTML = secondTen;
   secondBit = 9;
   secondBitTxt.innerHTML = secondBit;

   /*十分鐘過后*/
   if(minuteBit < 0){
   minuteTen--;
   minuteTenTxt.innerHTML = minuteTen;
   minuteBit = 9;
   minuteBitTxt.innerHTML = minuteBit;
   }

   /*一個小時過后*/
   if(minuteTen < 0){
   hour--;
   hourTxt.innerHTML = hour;
   minuteTen = 5;
   minuteTenTxt.innerHTML = minuteTen;
   minuteBit = 9;
   minuteBitTxt.innerHTML = minuteBit;
   secondTen = 5;
   secondTenTxt.innerHTML = secondTen;
   secondBit = 9;
   secondBitTxt.innerHTML = secondBit;
   }

   /*倒計時結束*/
   if(hour < 0 ){
   hour = 0;
   hourTxt.innerHTML = hour;
   minuteTen = 0;
   minuteTenTxt.innerHTML = minuteTen;
   minuteBit = 0;
   minuteBitTxt.innerHTML = minuteBit;
   secondTen = 0;
   secondTenTxt.innerHTML = secondTen;
   secondBit = 0;
   secondBitTxt.innerHTML = secondBit;
   clearTimeout(second);
   clearTimeout(start);
   }
  }
  }else{
  setTimeout(second,1000);
  }
 }
 setTimeout(second,1000);

 }
 setTimeout(start,1000);
}

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