VueJS

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.1.10/vue.min.js"></script>
<div id="app">
  <input type="text" @click="select" v-model="text" ref="input">
</div>

JavaScript

new Vue({
	el : '#app',
  data : {
   text: 'Some demo text'
  },
  methods : {
  	select() {
      this.$refs.input.select();
    }
  }
});