Vue 测试实例 - 自学教程(runoops.com)

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue 测试实例 - 自学教程(runoops.com)</title>


<script src="https://cdn.jsdelivr.net/npm/axios@0.12.0/dist/axios.min.js"></script>
<script src="https://unpkg.com/vue@next"></script>
</head>
<body>
<div id="watch-example">
  <p>
    输入一个问题，以 ? 号结尾输出答案:
    <input v-model="question" />
  </p>
  <p>{{ answer }}</p>
</div>  
<script>
const watchExampleVM = Vue.createApp({
   data() {
      return {
         question: '',
         answer: '每个问题结尾需要输入 ? 号。'
      }
   },
   watch: {
      // 每当问题改变时，此功能将运行，以 ? 号结尾
      question(newQuestion, oldQuestion) {
         if (newQuestion.indexOf('?') > -1) {
            this.getAnswer()
         }
      }
   },
   methods: {
      getAnswer() {
         this.answer = '加载中...'
         axios
            .get('https://yesno.wtf/api')
            .then(response => {
            this.answer = response.data.answer
         })
            .catch(error => {
            this.answer = '错误! 无法访问 API。 ' + error
         })
      }
   }
}).mount('#watch-example')
</script>
</body>
</html>