1 <template>
  2   <div class="dat-time">
  3     <div class="time-late">
  4       <span id="time_h1">{{time_h1}}</span>
  5       <span id="time_h2">{{time_h2}}</span>
  6       <span class="time-kong"></span>
  7       <span id="time_m1">{{time_m1}}</span>
  8
 
       <span id="time_m2">{{time_m2}}</span>
  9       <span class="time-kong"></span>
 10       <span id="time_s1">{{time_s1}}</span>
 11       <span id="time_s2">{{time_s2}}</span>
 12     </div>
 13   </div>
 14 </template>
 15 <script>
 16
 
 export default {
 17   name: "TimeDown",
 18   data() {
 19     return {
 20       content: "",
 21       time_s1: 0,
 22       time_s2: 0,
 23       time_m1: 0,
 24       time_m2: 0,
 25       time_h1: 0,
 26       time_h2: 0,
 27       timer:''
 28     };
 29   },
 30   props: {
 31     endTime: {
 32       //
 
父元件傳入的時間
 33       type: Number,
 34       default: ""
 35     },
 36     callback: {
 37       //倒計時結束的回撥函式
 38       type: Function,
 39       default: ""
 40     }
 41   },
 42   mounted() {
 43     this.countdowm(this.endTime); //呼叫計時器
 44   },
 45   destroyed() {
 46     clearInterval(_self.timer)//元件銷燬時銷燬計時器
 47   },
 48   methods: {
 49     countdowm(endTime) {
 50       let _self = this;
 51        _self.timer = setInterval(() => {
 52         if (endTime > 0) {//判斷倒計時剩餘的時間
 53           endTime--;
 54           _self.formateSeconds(endTime);//將秒數轉化為特定格式
 55         } else {//當倒計時時間小於0清除計時器
 56           clearInterval(_self.timer);
 57           _self._callback();//倒計時結束呼叫回撥函式
 58         }
 59       }, 1000);
 60     },
 61     //將秒轉化為時分秒
 62     formateSeconds(endTime) {
 63       let _self = this;
 64       let secondTime = parseInt(endTime);
 65       let minTime = 0;
 66       let hTime = 0;
 67       if (secondTime > 60) {
 68         minTime = parseInt(secondTime / 60);
 69         secondTime = parseInt(secondTime % 60);
 70         if (minTime > 60) {
 71           hTime = parseInt(minTime / 60);
 72           minTime = parseInt(minTime % 60);
 73         }
 74       }
 75       _self.time_s1 = _self.x(secondTime, 0, 1);
 76       _self.time_s2 = _self.x(secondTime, 1, 2);
 77       _self.time_m1 = _self.x(minTime, 0, 1);
 78       _self.time_m2 = _self.x(minTime, 1, 2);
 79       _self.time_h1 = _self.x(hTime, 0, 1);
 80       _self.time_h2 = _self.x(hTime, 1, 2);
 81     },
 82     x(num, s1, s2) {
 83       return num
 84         .toString()
 85         .padStart(2, 0)
 86         .substring(s1, s2);
 87     },
 88     _callback() {
 89       let _self = this;
 90       if (this.callback && this.callback instanceof Function) {
 91         _self.callback.call(_self);//呼叫回撥函式
 92       }
 93     }
 94   },
 95   //倒計時結束之後通過回撥函式重新獲取倒計時時間
 96   //通過watch監控
 97   watch: {
 98     endTime: {
 99       handler(nv, ov) {
100         if (!!nv) {//當獲取新的倒計時時間，啟動倒計時
101           this.countdowm(this.endTime);
102         }
103       }
104     }
105   }
106 };
107 </script>
108 <style scoped>
109 </style>

一個倒計時的小元件，有用請支援，有錯請指出