ionic3如何在弹出窗里写倒计时

Question

页面里有个确定，点击之后弹出一个弹出窗，没有button的弹出窗

定义了一个倒计时，倒计时能正常运行，
但是在弹出窗里，这个数字不改变
代码如下：
export class InteglePage {
public flag = true;
public num = 5;
constructor(public navCtrl: NavController, public navParams: NavParams, public alertCtrl: AlertController, public actionSheetCtrl: ActionSheetController) {
}

// 倒计时
shi() {

var countDown = document.getElementById('countDown');
console.log(countDown);
var timer = setInterval(() => {
  --this.num
  console.log(this.num);
  if (this.num <= 0) {
    clearInterval(timer)
  }
}, 1000);

}

`
agree() {

   this.shi();
    const confirm = this.alertCtrl.create({
          title: `<i class="icon iconfont">&#xe602;</i>`,
          message: `
              
              <h3>成功了</h3>
              <p><span id="countDown">${this.num}</span>秒跳转至首页</p>
              
          `,
          cssClass: "clickAgree",
        
        })
        confirm.present();

        setTimeout((data) => {
          confirm.dismiss(() => {
            console.log('dismissed')

          })
        }, 5000);
 }

`

Answer 1

原生的写法，获取dom元素，元素.innerHTML = num,就可以了
非常感谢

Answer 2

每次更新的时候隐藏并重新调用一下