<div id="act3">
<input v-model="form.firstname">

<!-- <btn @click="send()">send</btn> -->
 <button @click = 'send'>send</button>

 		<ul>
 			<li v-for="forms in form">
 				{{forms.firstname}}
 			</li>
 		</ul>


</div>
<script type="text/javascript" src="plugin/vue.js"></script>
<script type="text/javascript" src="plugin/act3.js"></script>

======================================================================
let x = new Vue({
     el:'#act3',
     data:{
          form: [
          {
               firstname:'romeo'
          }
          ],
     },
     methods:{
          send:function(){
               let newSomething =  Object.assign({}, newSomething,this.form.firstname)
               console.log(newSomething)
          }
     }
});