example

<div id="app">
  <h1>{{ name }}</h1>
</div>

const app = {
  data() {
    return {
      name: 'leedom'
    }
  }
}

Vue.createApp(app).mount('#app')

See the Pen MWbEJjj by leedom92 (@leedom92) on CodePen.

vue 2.0

<div id="app">
  <h1>{{ name }}</h1>
</div>

const app = new Vue({
  el: '#app',
  data: {
    name: 'leedom'
  }
})

See the Pen mdOBmwp by leedom92 (@leedom92) on CodePen.