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- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8">
- <meta http-equiv="X-UA-Compatible" content="IE=edge">
- <meta name="viewport" content="width=device-width, initial-scale=1.0">
- <title>Document</title>
- </head>
- <body>
- <div id="app">
- <button @click="change()">修改</button>
- <h2>姓： {{firstName}}</h2>
- <h2>名： {{lastName}}</h2>
- <h2>姓名: {{fullName}}</h2>
- </div>
- <script src="vue.js"></script>
- <script>
- var app = new Vue({
- el: "#app",
- data: {
- firstName: 'zhang',
- lastName: 'san',
- sex: '男'
- },
- methods: {
- change() {
- this.firstName = 'li'
- }
- },
- computed: {
- fullName: function () {
- console.log(333)
- return this.firstName + this.lastName
- }
- },
- watch: {
- firstName: function(){
- console.log('fffff')
- },
- lastName: function(){
- console.log('llllll')
- }
- }
- /*
- 在vue中 watch和computed都是用来观察数据变化的
- 作用不同
- watch是响应式数据变化并且进行相应的操作
- computed是用来计算一些基于响应式数据的操作
- computed 是带有一定缓存的 当响应式数据没有变化的时候 computed 不会重新计算
- */
- })
- </script>
- </body>
- </html>
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