## Checkbox
A group of options for multiple choices.
### Basic usage
Checkbox can be used alone to switch between two states.
:::demo Define `v-model`(bind variable) in `el-checkbox`. The default value is a `Boolean` for single `checkbox`, and it becomes `true` when selected. Content inside the `el-checkbox` tag will become the description following the button of the checkbox.
```html
Option
```
:::
### Disabled State
Disabled state for checkbox.
::: demo Set the `disabled` attribute.
```html
Option
Option
```
:::
### Checkbox group
It is used for multiple checkboxes which are bound in one group, and indicates whether one option is selected by checking if it is checked.
:::demo `checkbox-group` element can manage multiple checkboxes in one group by using `v-model` which is bound as an `Array`. Inside the `el-checkbox` element, `label` is the value of the checkbox. If no content is nested in that tag, `label` will be rendered as the description following the button of the checkbox. `label` also corresponds with the element values in the array. It is selected if the specified value exists in the array, and vice versa.
```html
```
:::
### Indeterminate
The `indeterminate` property can help you to achieve a 'check all' effect.
:::demo
```html
Check all
{{city}}
```
:::
### Minimum / Maximum items checked
The `min` and `max` properties can help you to limit the number of checked items.
:::demo
```html
{{city}}
```
:::
### Button style
Checkbox with button styles.
:::demo You just need to change `` element into `` element. We also provide `size` attribute for these buttons: `large` and `small`.
```html
{{city}}
{{city}}
{{city}}
```
:::
### Checkbox Attributes
| Attribute | Description | Type | Options | Default|
|---------- |-------- |---------- |------------- |-------- |
| label | value of the checkbox when used inside a `checkbox-group` | string | — | — |
| true-label | value of the checkbox if it's checked | string, number | — | — |
| false-label | value of the checkbox if it's not checked | string, number | — | — |
| name | native 'name' attribute | string | — | — |
| disabled | if the checkbox is disabled | boolean | — | false |
| checked | if the checkbox is checked | boolean | — | false |
| indeterminate | same as `indeterminate` in native checkbox | boolean | — | false |
### Checkbox-group Attributes
| Attribute | Description | Type | Options | Default|
|---------- |-------- |---------- |------------- |-------- |
|size | the size of checkbox buttons | string | large/small | —
|fill | border and background color when button is active | string | — | #20a0ff |
|text-color | font color when button is active | string | — | #ffffff |
| min | minimum number of checkbox checked | number | — | — |
| max | maximum number of checkbox checked | number | — | — |
### Checkbox Events
| Event Name | Description | Parameters |
|---------- |-------- |---------- |
| change | triggers when the binding value changes | Event object |