正确

练习：

编写缺失的代码，使观察者在数值低于40时激活警告类。

<div id="app"> <input type="range" v-model="rangeVal"> <p :class="{ warnClass: warnActive }"><code>{{ rangeVal }}</code></p> </div> <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script> <script> const app = Vue.createApp({ data() { return { rangeVal: 70, warnActive: false } }, watch: { rangeVal(val) { if(val<40){ this.warnActive = true; } else{ this.warnActive = false; } } } }) app.mount('#app') </script>

不正确

点击此处重试

正确

下一题 ❯

<div id="app">
  <input type="range" v-model="rangeVal">
  <p :class="{ warnClass: warnActive }"><code>{{ rangeVal }}</code></p> 
</div>

<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script>
  const app = Vue.createApp({
    data() {
      return {
        rangeVal: 70,
        warnActive: false
      }
    },
    watch: {
      w3exercise_input_no_0
 {
        if(val<40){
          this.warnActive = true;
        }
        else{
          this.warnActive = false;
        }
      }
    }
  })
 app.mount('#app')
</script>