<body>
<div id="root">
姓:<input v-model="firstName" />
名:<input v-model="lastName" />
<div>{{fullName}}</div>
</div>
</body>
<script>
new Vue({
el:'#root',
data:{
firstName:'',
lastName:'',
count:0
},
computed:{
fullName:function(){
return this.firstName+" "+this.lastName
}
},
watch:{
firstName:function(){
this.count++
},
lastName:function(){
this.count++
},
//或者
fullName:function(){
this.count++
},
}
});
</script>
methods ,在重新渲染的时候,函数总会重新调用执行。
computed:计算属性,是基于它的依赖缓存,只有相关依赖发生改变时才会重新取值。
watch: 侦听器监听属性变更,进行相应操作