<div id="app" v-cloak>
  	<button @click="doIt">Do It</button>
</div>
[v-cloak] {display: none}
Vue.config.productionTip = false;
Vue.config.devtools = false;

Vue.config.errorHandler = function(err, vm, info) {
  console.log(`Error: ${err.toString()}\nInfo: ${info}`);
}

Vue.config.warnHandler = function(msg, vm, trace) {
  console.log(`Warn: ${msg}\nTrace: ${trace}`);
}

const app = new Vue({
  el:'#app',
  methods:{
    doIt() {
      return x;
    }
  }
})

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://unpkg.com/vue@2