!DOCTYPE htmlhtml lang="en"head meta charset="UTF-8" meta name="viewport" content="width=device-width, initial-scale=1.0" meta http-equiv="X-UA-Compatible" content="ie=edge" titleDocument/title script src="./lib/vue-2.4.0.js"/script/headbod
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<script src="./lib/vue-2.4.0.js"></script>
</head>
<body>
<div id="app">
<!-- 分析： -->
<!-- 1. 我们要监听到 文本框数据的改变，这样才能知道 什么时候去拼接 出一个 fullname -->
<!-- 2. 如何监听到 文本框的数据改变呢？？？ -->
<input type="text" v-model="firstname" @keyup="getFullname"> +
<input type="text" v-model="lastname" @keyup="getFullname"> =
<input type="text" v-model="fullname">
</div>
<script>
// 创建 Vue 实例，得到 ViewModel
var vm = new Vue({
el: ‘#app‘,
data: {
firstname: ‘‘,
lastname: ‘‘,
fullname: ‘‘
},
methods: {
getFullname() {
this.fullname = this.firstname + ‘-‘ + this.lastname
}
}
});
</script>
</body>
</html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> <script src="./lib/vue-2.4.0.js"></script> </head> <body> <div id="app"> <input type="text" v-model="firstname"> + <input type="text" v-model="lastname"> = <input type="text" v-model="fullname"> </div> <script> // 创建 Vue 实例，得到 ViewModel var vm = new Vue({ el: ‘#app‘, data: { firstname: ‘‘, lastname: ‘‘, fullname: ‘‘ }, methods: {}, watch: { // 使用这个 属性，可以监视 data 中指定数据的变化，然后触发这个 watch 中对应的 function 处理函数 ‘firstname‘: function (newVal, oldVal) { // console.log(‘监视到了 firstname 的变化‘) // this.fullname = this.firstname + ‘-‘ + this.lastname // console.log(newVal + ‘ --- ‘ + oldVal) this.fullname = newVal + ‘-‘ + this.lastname }, ‘lastname‘: function (newVal) { this.fullname = this.firstname + ‘-‘ + newVal } } }); </script> </body> </html>