×

×

<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: { @(13) { if(val<40){ this.warnActive = true; } else{ this.warnActive = false; } } } }) app.mount('#app') </script>

<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

点击这里 重新尝试。

正确！

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