<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue 测试实例 - 菜鸟教程(runoob.com)</title>
<script src="https://cdn.staticfile.net/vue/2.4.2/vue.min.js"></script>
</head>
<body>
<div id = "computed_props">
千米 : <input type = "text" v-model = "kilometers">
米 : <input type = "text" v-model = "meters"><br/>
姓： <input type="text" v-model = "first_name">
名： <input type="text" v-model = "name">
</div>
<p id="info"></p>
<p id="info2"></p>
<script type = "text/javascript">
var vm = new Vue({
el: '#computed_props',
data: {
kilometers : 0,
meters:0,
first_name:"",
name:"",
},
methods: {
},
computed :{
},
watch : {
kilometers:function(val) {
this.kilometers = val;
this.meters = this.kilometers * 1000
},
meters : function (val) {
this.kilometers = val/ 1000;
this.meters = val;
},
first_name:function(val){
if(val == '张'){
this.first_name = val;
this.name = '三'
}else{
this.first_name = val;
this.name = ''
}
},
name:function(val){
if(val == '三'){
this.first_name = "张";
this.name = val
}else{
this.first_name = "";
this.name = val
}
}
}
});
// $watch 是一个实例方法
vm.$watch('kilometers', function (newValue, oldValue) {
// 这个回调将在 vm.kilometers 改变后调用
document.getElementById ("info").innerHTML = "修改前值为: " + oldValue + "，修改后值为: " + newValue;
});
vm.$watch('first_name', function (newValue, oldValue) {
// 这个回调将在 vm.kilometers 改变后调用
document.getElementById ("info2").innerHTML = "修改前值为: " + oldValue + "，修改后值为: " + newValue;
})
</script>
</body>
</html>
