HTML
<script src="https://unpkg.com/vue@2.6.11/dist/vue.js"></script>
<div id="app">
<input type="text" name="name" v-on:input="changeTitle" placeholder="Enter your name">
<p> {{ title }}</p>
</div>
JS
<script type="text/javascript">
new Vue({
el: "#app",
data: {
title : "Hello World"
},
methods : {
changeTitle: function(event){
this.title = event.target.value;
}
}
});
</script>
Output and Demo http://vue.toihid.com/section-1/4_extending_vuejs.php