12表单输入绑定
12.1基础用法
你可以用 v-model 指令在表单 <input>、<textarea> 及 <select> 元素上创建双向数据绑定。它会根据控件类型自动选取正确的方法来更新元素。
文本
<input v-model="message" placeholder="edit me">
<p>Message is: {{ message }}</p>
多行文本
<span>Multiline message is:</span>
<p style="white-space: pre-line;">{{ message }}</p>
<br>
<textarea v-model="message" placeholder="add multiple lines"></textarea>
复选框
单个复选框，绑定到布尔值：
<input type="checkbox" id="checkbox" v-model="checked">
<label for="checkbox">{{ checked }}</label>
多个复选框，绑定到同一个数组：
<div id='example-3'>
<input type="checkbox" id="jack" value="Jack" v-model="checkedNames">
<label for="jack">Jack</label>
<input type="checkbox" id="john" value="John" v-model="checkedNames">
<label for="john">John</label>
<input type="checkbox" id="mike" value="Mike" v-model="checkedNames">
<label for="mike">Mike</label>
<br>
<span>Checked names: {{ checkedNames }}</span>
</div>
new Vue({
el: '#example-3',
data: {
checkedNames: []
}
})
单选按钮
<div id="example-4">
<input type="radio" id="one" value="One" v-model="picked">
<label for="one">One</label>
<br>
<input type="radio" id="two" value="Two" v-model="picked">
<label for="two">Two</label>
<br>
<span>Picked: {{ picked }}</span>
</div>
new Vue({
el: '#example-4',
data: {
picked: ''
}
})
选择框
单选时：
<div id="example-5">
<select v-model="selected">
<option disabled value="">请选择</option>
<option>A</option>
<option>B</option>
<option>C</option>
</select>
<span>Selected: {{ selected }}</span>
</div>
new Vue({
el: '...',
data: {
selected: ''
}
})
多选时 (绑定到一个数组)：
<div id="example-6">
<select v-model="selected" multiple style="width: 50px;">
<option>A</option>
<option>B</option>
<option>C</option>
</select>
<br>
<span>Selected: {{ selected }}</span>
</div>
new Vue({
el: '#example-6',
data: {
selected: []
}
})
用 v-for 渲染的动态选项：
<select v-model="selected">
<option v-for="option in options" v-bind:value="option.value">
{{ option.text }}
</option>
</select>
<span>Selected: {{ selected }}</span>
new Vue({
el: '...',
data: {
selected: 'A',
options: [
{ text: 'One', value: 'A' },
{ text: 'Two', value: 'B' },
{ text: 'Three', value: 'C' }
]
}
})
12.2值绑定
对于单选按钮，复选框及选择框的选项，v-model 绑定的值通常是静态字符串 (对于复选框也可以是布尔值)：
<!-- 当选中时，`picked` 为字符串 "a" -->
<input type="radio" v-model="picked" value="a">
<!-- `toggle` 为 true 或 false -->
<input type="checkbox" v-model="toggle">
<!-- 当选中第一个选项时，`selected` 为字符串 "abc" -->
<select v-model="selected">
<option value="abc">ABC</option>
</select>
但是有时我们可能想把值绑定到 Vue 实例的一个动态属性上，这时可以用 v-bind 实现，并且这个属性的值可以不是字符串。
复选框
<input
type="checkbox"
v-model="toggle"
true-value="yes"
false-value="no"
>
// 当选中时
vm.toggle === 'yes'
// 当没有选中时
vm.toggle === 'no'
单选按钮
<input type="radio" v-model="pick" v-bind:value="a">
// 当选中时
vm.pick === vm.a
选择框的选项
<select v-model="selected">
<!-- 内联对象字面量 -->
<option v-bind:value="{ number: 123 }">123</option>
</select>
// 当选中时typeof vm.selected // => 'object'
vm.selected.number // => 123
12.3修饰符
.lazy
在默认情况下，v-model 在每次 input 事件触发后将输入框的值与数据进行同步 (除了上述输入法组合文字时)。你可以添加 lazy 修饰符，从而转变为使用 change 事件进行同步：
<!-- 在“change”时而非“input”时更新 -->
<input v-model.lazy="msg" >
.number
如果想自动将用户的输入值转为数值类型，可以给 v-model 添加 number 修饰符：
<input v-model.number="age" type="number">
这通常很有用，因为即使在 type="number" 时，HTML 输入元素的值也总会返回字符串。如果这个值无法被 parseFloat() 解析，则会返回原始的值。
.trim
如果要自动过滤用户输入的首尾空白字符，可以给 v-model 添加 trim 修饰符：
<input v-model.trim="msg">
完整代码：
12 表单输入绑定1.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<ul id="example-1">
<input v-model="message" placeholder="edit me">
<p>Message is: {{ message }}</p>
</ul>
<script>
var example1 = new Vue({
el: '#example-1',
data: {
message: ''
}
})
</script>
</body>
</html>
12 表单输入绑定2.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<ul id="example-2">
<span>Multiline message is:</span>
<p style="white-space: pre-line;">{{ message }}</p>
<br>
<textarea v-model="message" placeholder="add multiple lines"></textarea>
</ul>
<script>
var example1 = new Vue({
el: '#example-2',
data: {
message: ''
}
})
</script>
</body>
</html>
12 表单输入绑定3.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<ul id="example-3">
<input type="checkbox" id="checkbox" v-model="checked">
<label for="checkbox">{{ checked }}</label>
</ul>
<script>
var example1 = new Vue({
el: '#example-3',
data: {
checked: true
}
})
</script>
</body>
</html>
12 表单输入绑定4.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id='example-3'>
<input type="checkbox" id="jack" value="Jack" v-model="checkedNames">
<label for="jack">Jack</label>
<input type="checkbox" id="john" value="John" v-model="checkedNames">
<label for="john">John</label>
<input type="checkbox" id="mike" value="Mike" v-model="checkedNames">
<label for="mike">Mike</label>
<br>
<span>Checked names: {{ checkedNames }}</span>
</div>
<script>
new Vue({
el: '#example-3',
data: {
checkedNames: []
}
})
</script>
</body>
</html>
12 表单输入绑定5.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-4">
<input type="radio" id="one" value="One" v-model="picked">
<label for="one">One</label>
<br>
<input type="radio" id="two" value="Two" v-model="picked">
<label for="two">Two</label>
<br>
<span>Picked: {{ picked }}</span>
</div>
<script>
new Vue({
el: '#example-4',
data: {
picked: ''
}
})
</script>
</body>
</html>
12 表单输入绑定6.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-5">
<select v-model="selected">
<option disabled value="">请选择</option>
<option>A</option>
<option>B</option>
<option>C</option>
</select>
<span>Selected: {{ selected }}</span>
</div>
<script>
new Vue({
el: '#example-5',
data: {
selected: ''
}
})
</script>
</body>
</html>
12 表单输入绑定7.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-6">
<select v-model="selected" multiple style="width: 50px;">
<option>A</option>
<option>B</option>
<option>C</option>
</select>
<br>
<span>Selected: {{ selected }}</span>
</div>
<script>
new Vue({
el: '#example-6',
data: {
selected: []
}
})
</script>
</body>
</html>
12 表单输入绑定8.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-6">
<select v-model="selected">
<option v-for="option in options" v-bind:value="option.value">
{{ option.text }}
</option>
</select>
<span>Selected: {{ selected }}</span>
</div>
<script>
new Vue({
el: '#example-6',
data: {
selected: 'A',
options: [
{ text: 'One', value: 'A' },
{ text: 'Two', value: 'B' },
{ text: 'Three', value: 'C' }
]
}
})
</script>
</body>
</html>
12 表单输入绑定9.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-6">
<!-- 当选中时，`picked` 为字符串 "a" -->
<input type="radio" v-model="picked" value="a"><br>
{{picked}}
<!-- `toggle` 为 true 或 false -->
<input type="checkbox" v-model="toggle"><br>
{{toggle}}
<!-- 当选中第一个选项时，`selected` 为字符串 "abc" -->
<select v-model="selected">
<option value="a">aaa</option>
<option value="b">bbb</option>
<option value="c">ccc</option>
</select><br>
{{selected}}
<input
type="checkbox"
v-model="toggle"
true-value="yes"
false-value="no"
>
<input type="radio" v-model="pick" v-bind:value="a" v-on:click="onClick">
<select v-model="selected">
<!-- 内联对象字面量 -->
<option v-bind:value="{ number: 123 }">123</option>
</select>
</div>
<script>
new Vue({
el: '#example-6',
data: {
picked: '',
toggle: true,
selected: '',
pick: false
},
methods: {
onClick: function () {
alert(this.pick === this.a)
}
}
})
</script>
</body>
</html>
12 表单输入绑定10.html
<!DOCTYPE html>
<html>
<head>
<title>表单输入绑定</title>
<script src="
https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="example-6">
<!-- 在“change”时而非“input”时更新 -->
<input v-model.lazy="msg" >
{{msg}}
<br>
<input v-model.number="age" type="number">
{{age}}
<br>
<input v-model.trim="msg2">
{{msg2}}
</div>
<script>
new Vue({
el: '#example-6',
data: {
msg: '',
age: 0,
msg2: ''
},
methods: {
}
})
</script>
</body>
</html>
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