vue 基础之基本指令


1:指令v-cloak 的用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
[v-cloak]{
display: none;
}
</style>
</head>
<body>
<div id="app">
<div v-cloak>{{msg}}</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
v-cloak指令的用法
1、提供样式
[v-cloak]{
display: none;
}
2、在插值表达式所在的标签中添加v-cloak指令

背后的原理:先通过样式隐藏内容,然后在内存中进行值的替换,替换好之后再显示最终的结果
*/
var vm = new Vue({
el: '#app',
data: {
msg: 'Hello Vue'
}
});
</script>
</body>
</html>


2:数据填充相关的3个指令



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<div>{{msg}}</div>
<div v-text='msg'></div>
<div v-html='msg1'></div>
<div v-pre>{{msg}}</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
1、v-text指令用于将数据填充到标签中,作用于插值表达式类似,但是没有闪动问题
2、v-html指令用于将HTML片段填充到标签中,但是可能有安全问题
3、v-pre用于显示原始信息
*/
var vm = new Vue({
el: '#app',
data: {
msg: 'Hello Vue',
msg1: '<h1>HTML</h1>'
}
});
</script>
</body>
</html>


3:指令v-once 的用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<div>{{msg}}</div>
<div v-once>{{info}}</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
v-once的应用场景:如果显示的信息后续不需要再修改,你们可以使用v-once,这样可以提高性能。
*/
var vm = new Vue({
el: '#app',
data: {
msg: 'Hello Vue',
info: 'nihao'
}
});
</script>
</body>
</html>


4:-双向数据绑定



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<div>{{msg}}</div>
<div>
<input type="text" v-model='msg'>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
双向数据绑定
1、从页面到数据
2、从数据到页面
*/
var vm = new Vue({
el: '#app',
data: {
msg: 'Hello Vue'
}
});
</script>
</body>
</html>


5-事件的基本用法



<!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<title>Document</title>
</head>

<body>
<div id="app">
<div>{{num}}</div>
<div>
<button v-on:click='num++'>点击</button>
<button @click='num++'>点击1</button>
<button @click='handle'>点击2</button>
<button @click='handle()'>点击3</button>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
var vm = new Vue({
el: '#app',
data: {

num: 0

}, // 注意点: 这里不要忘记加逗号
// methods 中 主要是定义一些函数
methods: {

handle: function() {
// 这里的this是Vue的实例对象+
console.log(this === vm)
// 在函数中 想要使用data里面的数据 一定要加this
this.num++;
}
}
});
</script>
</body>

</html>


6:事件函数传参



<!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<title>Document</title>
</head>

<body>
<div id="app">
<div>{{num}}</div>
<div>
<!-- 如果事件直接绑定函数名称,那么默认会传递事件对象作为事件函数的第一个参数 -->
<button v-on:click='handle1'>点击1</button>
<!-- 2、如果事件绑定函数调用,那么事件对象必须作为最后一个参数显示传递,
并且事件对象的名称必须是$event
-->
<button v-on:click='handle2(123, 456, $event)'>点击2</button>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
var vm = new Vue({
el: '#app',
data: {
num: 0
},
methods: {
handle1: function(event) {
console.log(event.target.innerHTML)
},
handle2: function(p, p1, event) {
console.log(p, p1)
console.log(event.target.innerHTML)
this.num++;
}
}
});
</script>
</body>

</html>


7:事件修饰符



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
/*
1、通过属性选择器 选择到 带有属性 v-cloak的标签
让他隐藏
*/

[v-cloak] {
display: none;
}
</style>
</head>
<body>
<div id="app">
<div v-cloak>{{num}}</div>
<div v-on:click='handle0'>
<button v-on:click.stop='handle1'>点击1</button>
</div>
<div>
<a href="http://www.baidu.com" v-on:click.prevent='handle2'>百度</a>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
事件绑定-事件修饰符
*/
var vm = new Vue({
el: '#app',
data: {
num: 0
},
methods: {
handle0: function(){
this.num++;
},
handle1: function(event){
// 阻止冒泡
// event.stopPropagation();
},
handle2: function(event){
// 阻止默认行为
//prevent 防止
// event.preventDefault();
}
}
});
</script>
</body>
</html>


8-按键修饰符



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<form action="">
<div>
用户名:
<input type="text" v-on:keyup.delete='clearContent' v-model='uname'>
</div>
<div>
密码:
<input type="text" v-on:keyup.f1='handleSubmit' v-model='pwd'>
</div>
<div>
<input type="button" v-on:click='handleSubmit' value="提交">
</div>
</form>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
事件绑定-按键修饰符
*/
Vue.config.keyCodes.f1 = 113
var vm = new Vue({
el: '#app',
data: {
uname: '',
pwd: '',
age: 0
},
methods: {
clearContent:function(){
// 按delete键的时候,清空用户名
this.uname = '';
},
handleSubmit: function(){
console.log(this.uname,this.pwd)
}
}
});
</script>
</body>
</html>


9-自定义事件修饰符



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<input type="text" v-on:keyup.aaa='handle' v-model='info'>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
事件绑定-自定义按键修饰符
规则:自定义按键修饰符名字是自定义的,但是对应的值必须是按键对应event.keyCode值
*/
Vue.config.keyCodes.aaa = 65
var vm = new Vue({
el: '#app',
data: {
info: ''
},
methods: {
handle: function(event){
console.log(event.keyCode)
}
}
});
</script>
</body>
</html>


10-简单的计算器案列



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<h1>简单计算器</h1>
<div>
<span>数值A:</span>
<span>
<input type="text" v-model='a'>
</span>
</div>
<div>
<span>数值B:</span>
<span>
<input type="text" v-model='b'>
</span>
</div>
<div>
<button v-on:click='handle'>计算</button>
</div>
<div>
<span>计算结果:</span>
<span v-text='result'></span>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
简单计算器案例
*/
var vm = new Vue({
el: '#app',
data: {
a: '',
b: '',
result: ''
},
methods: {
handle: function(){
// 实现计算逻辑
this.result = parseInt(this.a) + parseInt(this.b);
}
}
});
</script>
</body>
</html>


11-属性绑定的基本用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<a v-bind:href="url">百度</a>
<a :href="url">百度1</a>
<button v-on:click='handle'>切换</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
属性绑定
*/
var vm = new Vue({
el: '#app',
data: {
url: 'http://www.baidu.com'
},
methods: {
handle: function(){
// 修改URL地址
this.url = 'http://itcast.cn';
}
}
});
</script>
</body>
</html>


12-v-model 的本质



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="app">
<div>{{msg}}</div>
<input type="text" v-bind:value="msg" v-on:input='handle'>
<input type="text" v-bind:value="msg" v-on:input='msg=$event.target.value'>
<input type="text" v-model='msg'>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
v-model指令的本质

*/
var vm = new Vue({
el: '#app',
data: {
msg: 'hello'
},
methods: {
handle: function(event){
// 使用输入域中的最新的数据覆盖原来的数据
this.msg = event.target.value;
}
}
});
</script>
</body>
</html>


13-样式绑定之class绑定对象的用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
.active {
border: 1px solid red;
width: 100px;
height: 100px;
}
.error {
background-color: orange;
}
</style>
</head>
<body>
<div id="app">
<div v-bind:class="{active: isActive,error: isError}">
测试样式
</div>
<button v-on:click='handle'>切换</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
样式绑定

*/
var vm = new Vue({
el: '#app',
data: {
isActive: true,
isError: true
},
methods: {
handle: function(){
// 控制isActive的值在true和false之间进行切换
this.isActive = !this.isActive;
this.isError = !this.isError;
}
}
});
</script>
</body>
</html>


14-样式绑定之class绑定数组的用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
.active {
border: 1px solid red;
width: 100px;
height: 100px;
}
.error {
background-color: orange;
}
</style>
</head>
<body>
<div id="app">
<div v-bind:class='[activeClass, errorClass]'>测试样式</div>
<button v-on:click='handle'>切换</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
样式绑定

*/
var vm = new Vue({
el: '#app',
data: {
activeClass: 'active',
errorClass: 'error'
},
methods: {
handle: function(){
this.activeClass = '';
this.errorClass = '';
}
}
});
</script>
</body>
</html>


15-样式绑定的之class绑定的3个细节用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
.active {
border: 1px solid red;
width: 100px;
height: 100px;
}
.error {
background-color: orange;
}
.test {
color: blue;
}
.base {
font-size: 28px;
}
</style>
</head>
<body>
<div id="app">
<div v-bind:class='[activeClass, errorClass, {test: isTest}]'>测试样式</div>
<div v-bind:class='arrClasses'></div>
<div v-bind:class='objClasses'></div>
<div class="base" v-bind:class='objClasses'></div>

<button v-on:click='handle'>切换</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
样式绑定相关语法细节:
1、对象绑定和数组绑定可以结合使用
2、class绑定的值可以简化操作
3、默认的class如何处理?默认的class会保留

*/
var vm = new Vue({
el: '#app',
data: {
activeClass: 'active',
errorClass: 'error',
isTest: true,
arrClasses: ['active','error'],
objClasses: {
active: true,
error: true
}
},
methods: {
handle: function(){
// this.isTest = false;
this.objClasses.error = false;
}
}
});
</script>
</body>
</html>


16-样式绑定之style绑定用法



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>

</head>
<body>
<div id="app">
<div v-bind:style='{border: borderStyle, width: widthStyle, height: heightStyle}'></div>
<div v-bind:style='objStyles'></div>
<div v-bind:style='[objStyles, overrideStyles]'></div>
<button v-on:click='handle'>切换</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
样式绑定之内联样式Style:

*/
var vm = new Vue({
el: '#app',
data: {
borderStyle: '1px solid blue',
widthStyle: '100px',
heightStyle: '200px',
objStyles: {
border: '1px solid green',
width: '200px',
height: '100px'
},
overrideStyles: {
border: '5px solid orange',
backgroundColor: 'blue'
}
},
methods: {
handle: function(){
this.heightStyle = '100px';
this.objStyles.width = '100px';
}
}
});
</script>
</body>
</html>


17:分支结构



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>

</head>
<body>
<div id="app">
<div v-if='score>=90'>优秀</div>
<div v-else-if='score<90&&score>=80'>良好</div>
<div v-else-if='score<80&&score>60'>一般</div>
<div v-else>比较差</div>
<div v-show='flag'>测试v-show</div>
<button v-on:click='handle'>点击</button>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
分支结构

v-show的原理:控制元素样式是否显示 display:none
*/
var vm = new Vue({
el: '#app',
data: {
score: 10,
flag: false
},
methods: {
handle: function(){
this.flag = !this.flag;
}
}
});
</script>
</body>
</html>


19:循环结构便利数组



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>

</head>
<body>
<div id="app">
<div>水果列表</div>
<ul>
<li v-for='item in fruits'>{{item}}</li>
<li v-for='(item, index) in fruits'>{{item + '---' + index}}</li>
<li :key='item.id' v-for='(item, index) in myFruits'>
<span>{{item.ename}}</span>
<span>-----</span>
<span>{{item.cname}}</span>
</li>

</ul>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*
循环结构-遍历数组
*/
var vm = new Vue({
el: '#app',
data: {
fruits: ['apple', 'orange', 'banana'],
myFruits: [{
id: 1,
ename: 'apple',
cname: '苹果'
},{
id: 2,
ename: 'orange',
cname: '橘子'
},{
id: 3,
ename: 'banana',
cname: '香蕉'
}]
}
});
</script>
</body>
</html>


20:循环结构遍历对象



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>

</head>
<body>
<div id="app">
<div v-if='v==13' v-for='(v,k,i) in obj'>{{v + '---' + k + '---' + i}}</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
// 使用原生js遍历对象
var obj = {
uname: 'lisi',
age: 12,
gender: 'male'
}
for(var key in obj) {
console.log(key, obj[key])
}
/*
循环结构
*/
var vm = new Vue({
el: '#app',
data: {
obj: {
uname: 'zhangsan',
age: 13,
gender: 'female'
}
}
});
</script>
</body>
</html>


20-选项卡案例



<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">

.tab ul {
overflow: hidden;
padding: 0;
margin: 0;
}
.tab ul li {
box-sizing: border-box;
padding: 0;
float: left;
width: 100px;
height: 45px;
line-height: 45px;
list-style: none;
text-align: center;
border-top: 1px solid blue;
border-right: 1px solid blue;
cursor
}
.tab ul li:first-child {
border-left: 1px solid blue;
}
.tab ul li.active {
background-color: orange;
}
.tab div {
width: 500px;
height: 300px;
display: none;
text-align: center;
font-size: 30px;
line-height: 300px;
border: 1px solid blue;
border-top: 0px;
}
.tab div.current {
display: block;
}
</style>
</head>
<body>
<div id="app">
<div class="tab">
<ul>
<li v-on:click='change(index)' :class='currentIndex==index?"active":""' :key='item.id' v-for='(item,index) in list'>{{item.title}}</li>
</ul>
<div :class='currentIndex==index?"current":""' :key='item.id' v-for='(item, index) in list'>
<img :src="item.path">
</div>
</div>
</div>
<script type="text/javascript" src="js/vue.js"></script>
<script type="text/javascript">
/*

*/
var vm = new Vue({
el: '#app',
data: {
currentIndex: 0, // 选项卡当前的索引
list: [{
id: 1,
title: 'apple',
path: 'img/apple.png'
},{
id: 2,
title: 'orange',
path: 'img/orange.png'
},{
id: 3,
title: 'lemon',
path: 'img/lemon.png'
}]
},
methods: {
change: function(index){
// 在这里实现选项卡切换操作:本质就是操作类名
// 如何操作类名?就是通过currentIndex
this.currentIndex = index;
}
}
});
</script>
</body>
</html>