vue calculated property and watch blocking properties and events

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This link: https://blog.csdn.net/caoxuecheng001/article/details/102757284

1, to prevent the event bubbling

 <button @click.stop="print('button')">点我试试啊</button>

2, to prevent the page jump

<a href="http://www.baidu.com" @click.prevent ="print('我是百度')">百度一下，你就知道</a>

3, attributes, and calculates attributes watch

const app=new Vue({
       el:"#app",
       data:{
            num:1,
           isRed:true,
            birthday:152903215210,
           person:{
                name:"Jack",
                age:12
           }
       },
       computed:{
           birth(){
                const day=new Date(this.birthday);
                return day.getFullYear()+"年"+day.getMonth()+"月"+day.getDay()+"日";
           }
       },
       watch:{
           num(val,oldval){
               console.log(val,oldval)
           },
           person:{
               deep:true,
               handler(val) {
                    console.log(val.age)
               }
           }
       }
   });

   <h1>
        您的生日：{{birth}}
    </h1>
    <!-- watch-->
    <input type="text" v-model="num">
    <h1>num:{{num}}</h1>