1.插值
插值:用双大括号{{}}将数据绑定到模板中,实现简单的数据渲染。例如:<p>{{message}}</p>,其中message是一个变量。
1.1.3 属性
HTML属性中的值应使用v-bind指令
1.1.4 表达式
1.1.1 文本
{{msg}
1.1.2 html
使用v-html
Vue提供了完全的JavaScript表达式支持
效果如下:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>入门</title>
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<style type="text/css">
.f30{
font-size: 30px;
}
</style>
</head>
<body>
<div id="app">
{{msg}}
<p>html解析</p>
{{msg2}}
<b :class="msg3" v-html="msg2"></b>
{{msg4+1}}
{{sb.substring(3,8)}}
<input v-model="ok">
{{ok==1? "你好我是雪豹":"妈妈每天都给我抽点支烟,以及听雪"}}
</div>
<script type="text/javascript">
new Vue({
el:"#app",
data(){
return {msg:'hellow 你好 vue',
msg2:'<span style="color:yellow">hello 你好vue </span>',
msg3:'f30',
msg4:5,
ok:1,
sb:'邓郑伟学坤坤跳舞'
}
}
})
</script>
</body>
</html>
2.指令:
用v-开头的特殊属性,可以实现DOM操作、条件渲染、循环、事件绑定等功能。例如:<p v-if="isShow">{{message}}</p>,其中v-if是条件渲染的指令。
核心指令
(v-if|v-else|v-else-if)/v-show/v-for/v-bind/v-on/v-model
v-if|v-else|v-else-if:根据其后表达式的bool值进行判断是否渲染该元素
他们只能是兄弟元素
v-else-if上一个兄弟元素必须是v-if
v-else上一个兄弟元素必须是v-if或者是v-else-if
v-show:与v-if类似,只是会渲染其身后表达式为false的元素,而且会给这样的元素添加css代码:style="display:none"
v-for:类似JS的遍历,
遍历数组: v-for="item in items", items是数组,item为数组中的数组元素
遍历对象: v-for="(value,key,index) in stu", value属性值,key属性名,index下标
v-bind
v-on
v-model:用来在 input、select、textarea、checkbox、radio 等表单控件元素上创建双向数据绑定,根据表单上的值,自动更新绑定的元素的值
v-for/v-model一起绑定[多选]复选框和单选框
使用:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<title>指令</title>
</head>
<body>
<div id="app">
<input v-model="score">
<b v-if="score < 60 ">不及格</b>
<b v-else-if="score >= 60 && score <70 ">及格</b>
<b v-else-if="score >= 70 && score <80 ">中等</b>
<b v-else-if="score >= 80 && score <90 ">良好</b>
<b v-else="score >=90 && score <100>">优秀</b>
<b>{{array}}</b>
<i v-for="a in array">{{a}}||</i>
<i v-for="u in User">{{u.name}}喜欢{{u.hobby}}今年{{u.age}}</i>
<br />
<select>
<option v-for="h in hobby" :value="h.id">
{{h.name}}
</option></select>
<br />
<div v-for="h in hobby"><input type="checkbox" name="hpbby" :value="h.id">{{h.name}}</div>
<p>v-show</p>
<div v-show="score>90">v-show-上优秀学员名单</div>
<div v-if="score>90">v-if-上优秀学员名单</div>
</div>
<script type="text/javascript">
new Vue({
el:'#app',
data(){
return {score:60,
array:[1,2,3,4],
User:[{name:'小威',hobby:'玩棒子',age:18},
{name:'小威',hobby:'玩棒子',age:18},
{name:'小威',hobby:'玩棒子',age:18}],
hobby:[{id:1,name:'洗脚'},
{id:2,name:'保健'},
{id:3,name:'按摩'},
{id:4,name:'spa'}]
}
}
})
</script>
</body>
</html>
效果:
3.动态参数
动态参数:除了用固定的指令名称,还可以使用动态参数来动态绑定数据。例如:<a v-bind:href="url">{{ message }}</a>,其中v-bind动态绑定href属性的值。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<title>指令</title>
</head>
<body>
<div id="app">
<input v-model="score">
<b v-if="score < 60 ">不及格</b>
<b v-else-if="score >= 60 && score <70 ">及格</b>
<b v-else-if="score >= 70 && score <80 ">中等</b>
<b v-else-if="score >= 80 && score <90 ">良好</b>
<b v-else="score >=90 && score <100>">优秀</b>
<b>{{array}}</b>
<i v-for="a in array">{{a}}||</i>
<i v-for="u in User">{{u.name}}喜欢{{u.hobby}}今年{{u.age}}</i>
<br />
<select>
<option v-for="h in hobby" :value="h.id">
{{h.name}}
</option></select>
<br />
<div v-for="h in hobby"><input type="checkbox" name="hpbby" :value="h.id">{{h.name}}</div>
<p>v-show</p>
<div v-show="score>90">v-show-上优秀学员名单</div>
<div v-if="score>90">v-if-上优秀学员名单</div>
<p>动态参数</p>
<input v-model="evname"/>
<button v-on:[evname]="test">点我</button>
</div>
<script type="text/javascript">
new Vue({
el:'#app',
data(){
return {score:60,
array:[1,2,3,4],
User:[{name:'小威',hobby:'玩棒子',age:18},
{name:'小威',hobby:'玩棒子',age:18},
{name:'小威',hobby:'玩棒子',age:18}],
hobby:[{id:1,name:'洗脚'},
{id:2,name:'保健'},
{id:3,name:'按摩'},
{id:4,name:'spa'}],
evname:'click'
};
}
,methods:{
test(){
alert("点我试试")
}
}
})
</script>
</body>
</html>
4.过滤器
vue允许自定义过滤器,一般用于常见的文本格式化,过滤器可用的两个地方:双花括号插值与v-bind表达式,过滤器应该被添加在js表达式的尾部,使用管道运算符 " | "
局部过滤器
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<title>过滤器</title>
</head>
<body>
<div id='app'>
<p>局部过滤器</p>
{{msg}}
<p>局部过滤器串行使用</p>
{{msg | filterA | filterB}}
<p>局部过滤器传参</p>
{{msg | filterC(2,5)}}
</div>
<script type="text/javascript">
new Vue({
el:'#app',
filters:{
'filterA':function(v){
return v.substring(0,5);
},
'filterB':function(v){
return v.substring(2,5);
},
'filterC':function(v,begin,end){
return v.substring(begin,end);
}
},
data(){
return {
msg:'你好 饿了么'
}
}
})
</script>
</body>
</html>
全局过滤器
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<script src="date.js"></script>
<title>过滤器</title>
</head>
<body>
<div id='app'>
<p>局部过滤器</p>
{{msg}}
<p>局部过滤器串行使用</p>
{{msg | filterA | filterB}}
<p>局部过滤器传参</p>
{{msg | filterC(2,5)}}
<p>全局过滤器</p>
没有过滤器的结果: {{time}}
有过滤器的结果:{{time|fmtDate}}
<script src="js/date.js"></script>
</div>
<script type="text/javascript">
Vue.filter('fmtDate', function(value) {
return fmtDate(value, 'yyyy年MM月dd日')
});
new Vue({
el:'#app',
filters:{
'filterA':function(v){
return v.substring(0,5);
},
'filterB':function(v){
return v.substring(2,5);
},
'filterC':function(v,begin,end){
return v.substring(begin,end);
}
},
data(){
return {
msg:'你好 饿了么',
time:new Date()
}
}
})
</script>
</body>
</html>
data.js
//给Date类添加了一个新的实例方法format
Date.prototype.format = function (fmt) {
//debugger;
var o = {
"M+": this.getMonth() + 1, //月份
"d+": this.getDate(), //日
"h+": this.getHours(), //小时
"m+": this.getMinutes(), //分
"s+": this.getSeconds(), //秒
"q+": Math.floor((this.getMonth() + 3) / 3), //季度
"S": this.getMilliseconds() //毫秒
};
if (/(y+)/.test(fmt))
fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
for (var k in o)
if (new RegExp("(" + k + ")").test(fmt))
fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
return fmt;
};
function fmtDate(date, pattern) {
var ts = date.getTime();
var d = new Date(ts).format("yyyy-MM-dd hh:mm:ss");
if (pattern) {
d = new Date(ts).format(pattern);
}
return d.toLocaleString();
};
结果:
5.计算属性监听属性
计算属性
<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<meta charset="utf-8">
<title>计算属性监听属性</title>
</head>
<body>
<div id="app">
<p>计算属性</p>
单价:<input v-model="price">
数量:<input v-model="num">
小计:{{count}}
</div>
<script type="text/javascript">
new Vue({
el:'#app',
data(){
return {
price:79,
num:1
};
},
computed:{
count:function(){
return this.price*this.num
}
}
})
</script>
</body>
</html>
效果:
改为2
计算属性特点:一方影响另一方(单向)
监听属性:
<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<meta charset="utf-8">
<title>计算属性监听属性</title>
</head>
<body>
<div id="app">
<p>计算属性</p>
单价:<input v-model="price">
数量:<input v-model="num">
小计:{{count}}
<p>监听属性</p>
千米:<input v-model="km" />
米:<input v-model="m"/>
</div>
<script type="text/javascript">
new Vue({
el:'#app',
data(){
return {
price:79,
num:1,
m:1000,
km:1
};
},
computed:{
count:function(){
return this.price*this.num
}
},
watch:{
km:function(v){
this.m=parseInt(v) * 1000;
},
m:function(v){
this.km=parseInt(v) / 1000;
}
}
})
</script>
</body>
</html>
效果:
监听属性特点:两方互相影响(双向)
实战案例:
购物车:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>购物车</title>
<script src="https://cdn.bootcdn.net/ajax/libs/vue/2.6.10/vue.js"></script>
<style>
.container {
width: 600px;
margin: 0 auto;
}
table {
border-collapse: collapse;
width: 100%;
}
table td {
border: 1px solid #ddd;
padding: 10px;
text-align: center;
}
.input-wrapper {
display: flex;
justify-content: center;
align-items: center;
}
button {
padding: 5px 10px;
background-color: #eee;
border: none;
cursor: pointer;
}
</style>
</head>
<body>
<div id="app" class="container">
<p>购物车</p>
<table>
<thead>
<tr>
<th>物品</th>
<th>单价</th>
<th>数量</th>
<th>小计</th>
</tr>
</thead>
<tbody>
<tr v-for="(item, index) in items" :key="index">
<td>{{ item.name }}</td>
<td>{{ item.price }}</td>
<td class="input-wrapper">
<button @click="decrement(index)">-</button>
<input v-model="item.quantity" />
<button @click="increment(index)">+</button>
</td>
<td>{{ item.price * item.quantity }}</td>
</tr>
<tr>
<td colspan="3">总价</td>
<td>{{ total }}</td>
</tr>
</tbody>
</table>
</div>
<script type="text/javascript">
new Vue({
el: '#app',
data() {
return {
items: [
{ name: '帽子', price: 10, quantity: 1 },
{ name: '衣服', price: 30, quantity: 1 },
{ name: '裤子', price: 20, quantity: 1 },
{ name: '肾宝片', price: 200, quantity: 1 },
{ name: '羊腰子', price: 20, quantity: 1 },
],
};
},
methods: {
increment(index) {
this.items[index].quantity++;
},
decrement(index) {
if (this.items[index].quantity > 1) {
this.items[index].quantity--;
}
},
},
computed: {
total() {
return this.items.reduce((sum, item) => sum + (item.price * item.quantity), 0);
},
},
});
</script>
</body>
</html>
效果: