console 命令行工具 X clear

console

new Vue({
  el: '#app',
  data: {
    isActive: true
  }
})

<div id="app">
  <div v-bind:class="{ active: isActive }">
  </div>
</div>

.active {
  width: 100px;
  height: 100px;
  background: green;
}