1.定义一个定时器常量

 const timer = ref(null);

2.在 onMounted 里初始化定时器

onMounted(() => {
    init(props.ydbh);
    timer.value = setInterval(async () => {
      activeStep.value = await init(props.ydbh);
    }, 5000);
  });

3.离开页面时销毁

onUnmounted(() => {
    clearInterval(timer.value);
  });