JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//unpkg.com/vue/dist/vue.js"></script>
<script src="//unpkg.com/element-ui/lib/index.js"></script>
<div id="app">
<el-input v-model="input" placeholder="请输入内容" ref="input1"></el-input>
<el-button @click="focus">获取焦点</el-button>
</div>

SCSS

@import url("//unpkg.com/element-ui/lib/theme-default/index.css");

.el-button {
  margin-top: 20px;
}

Babel + JSX

var Main = {
  data() {
    return {
      input: ''
    }
  },
  methods: {
    focus() {
      this.$refs.input.$el.querySelector('input').focus();
    }
  }
}
var Ctor = Vue.extend(Main)
new Ctor().$mount('#app')