实现Vue.js组件，以便将元素定义为|软件开发问答库

<div><label for="username">Username: </label><input type="text" id="username"></div> <div id="app"> <labeledinput id="username">Username: </labeledinput> </div> <script> var vm = new Vue({ el: '#app' }); // Example case console.log(document.getElementById("app").innerHTML); </script>

创建组件更简单的方法是：

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
  </head>
  <body>
    <div id="app">
      <div>
        <label-input v-model="username">
          <span>Username</span>
        </label-input>
        <span>Username is {{ username }}</span>
      </div>
    </div>
    <script>
      Vue.component('label-input', {
        props: ['value'],
        template: `
          <div>
            <label>
              <slot></slot>
              <input type="text" :value="value" @input="$emit('input', $event.target.value)" />
            </label>
          </div>`,
      });

      new Vue({
        el: '#app',
        data() {
          return {
            username: '',
          };
        },
      });
    </script>
  </body>
</html>