## 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
<template>
  <div>
    <el-checkbox v-model="checked1" label="Option 1"></el-checkbox>
    <el-checkbox v-model="checked2" label="Option 2"></el-checkbox>
  </div>
  <div>
    <el-checkbox
      v-model="checked3"
      label="Option 1"
      size="medium"
    ></el-checkbox>
    <el-checkbox
      v-model="checked4"
      label="Option 2"
      size="medium"
    ></el-checkbox>
  </div>
  <div>
    <el-checkbox v-model="checked5" label="Option 1" size="small"></el-checkbox>
    <el-checkbox v-model="checked6" label="Option 2" size="small"></el-checkbox>
  </div>
  <div>
    <el-checkbox v-model="checked7" label="Option 1" size="mini"></el-checkbox>
    <el-checkbox v-model="checked8" label="Option 2" size="mini"></el-checkbox>
  </div>
</template>
<script>
  export default {
    data() {
      return {
        checked1: true,
        checked2: false,
        checked3: false,
        checked4: false,
        checked5: false,
        checked6: false,
        checked7: false,
        checked8: false,
      }
    },
  }
</script>
<!--
<setup>

  import { defineComponent, ref } from 'vue';

  export default defineComponent({
    setup() {
      const checked1 = ref(true);
      const checked2 = ref(false);
      const checked3 = ref(false);
      const checked4 = ref(false);
      const checked5 = ref(false);
      const checked6 = ref(false);
      const checked7 = ref(false);
      const checked8 = ref(false);
      return {
        checked1,
        checked2,
        checked3,
        checked4,
        checked5,
        checked6,
        checked7,
        checked8,
      };
    },
  });

</setup>
-->
```

:::

### Disabled State

Disabled state for checkbox.

:::demo Set the `disabled` attribute.

```html
<template>
  <el-checkbox v-model="checked1" disabled>Option</el-checkbox>
  <el-checkbox v-model="checked2" disabled>Option</el-checkbox>
</template>
<script>
  export default {
    data() {
      return {
        checked1: false,
        checked2: true,
      }
    },
  }
</script>
<!--
<setup>

  import { defineComponent, ref } from 'vue';

  export default defineComponent({
    setup() {
      const checked1 = ref(false);
      const checked2 = ref(true);
      return {
        checked1,
        checked2,
      };
    },
  });
</setup>
-->
```

:::

### 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
<template>
  <el-checkbox-group v-model="checkList">
    <el-checkbox label="Option A"></el-checkbox>
    <el-checkbox label="Option B"></el-checkbox>
    <el-checkbox label="Option C"></el-checkbox>
    <el-checkbox label="disabled" disabled></el-checkbox>
    <el-checkbox label="selected and disabled" disabled></el-checkbox>
  </el-checkbox-group>
</template>

<script>
  export default {
    data() {
      return {
        checkList: ['selected and disabled', 'Option A'],
      }
    },
  }
</script>
<!--
<setup>

  import { defineComponent, ref } from 'vue';

  export default defineComponent({
    setup() {
      const checkList = ref(['selected and disabled','Option A']);
      return {
        checkList,
      };
    },
  });

</setup>
-->
```

:::

### Indeterminate

The `indeterminate` property can help you to achieve a 'check all' effect.

:::demo

```html
<template>
  <el-checkbox
    :indeterminate="isIndeterminate"
    v-model="checkAll"
    @change="handleCheckAllChange"
    >Check all</el-checkbox
  >
  <el-checkbox-group
    v-model="checkedCities"
    @change="handleCheckedCitiesChange"
  >
    <el-checkbox v-for="city in cities" :label="city" :key="city"
      >{{city}}</el-checkbox
    >
  </el-checkbox-group>
</template>
<script>
  const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen']
  export default {
    data() {
      return {
        checkAll: false,
        checkedCities: ['Shanghai', 'Beijing'],
        cities: cityOptions,
        isIndeterminate: true,
      }
    },
    methods: {
      handleCheckAllChange(val) {
        this.checkedCities = val ? cityOptions : []
        this.isIndeterminate = false
      },
      handleCheckedCitiesChange(value) {
        let checkedCount = value.length
        this.checkAll = checkedCount === this.cities.length
        this.isIndeterminate =
          checkedCount > 0 && checkedCount < this.cities.length
      },
    },
  }
</script>
<!--
<setup>

  import { defineComponent, reactive, toRefs } from 'vue';

  const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen'];

  export default defineComponent({
    setup() {
      const state = reactive({
        checkAll: false,
        checkedCities: ['Shanghai', 'Beijing'],
        cities: cityOptions,
        isIndeterminate: true,
      });
      const handleCheckAllChange = (val) => {
        state.checkedCities = val ? cityOptions : [];
        state.isIndeterminate = false;
      };
      const handleCheckedCitiesChange = (value) => {
        const checkedCount = value.length;
        state.checkAll = checkedCount === state.cities.length;
        state.isIndeterminate = checkedCount > 0 && checkedCount < state.cities.length;
      };
      return {
        ...toRefs(state),
        handleCheckAllChange,
        handleCheckedCitiesChange,
      };
    },
  });

</setup>
-->
```

:::

### Minimum / Maximum items checked

The `min` and `max` properties can help you to limit the number of checked items.

:::demo

```html
<template>
  <el-checkbox-group v-model="checkedCities" :min="1" :max="2">
    <el-checkbox v-for="city in cities" :label="city" :key="city"
      >{{city}}</el-checkbox
    >
  </el-checkbox-group>
</template>
<script>
  const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen']
  export default {
    data() {
      return {
        checkedCities: ['Shanghai', 'Beijing'],
        cities: cityOptions,
      }
    },
  }
</script>
<!--
<setup>

  import { defineComponent, reactive, toRefs } from 'vue';

  const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen'];

  export default defineComponent({
    setup() {
      const state = reactive({
        checkedCities: ['Shanghai', 'Beijing'],
        cities: cityOptions,
      });

      return {
        ...toRefs(state),
      };
    },
  });

</setup>
-->
```

:::

### Button style

Checkbox with button styles.

:::demo You just need to change `el-checkbox` element into `el-checkbox-button` element. We also provide `size` attribute.

```html
<template>
  <div>
    <el-checkbox-group v-model="checkboxGroup1">
      <el-checkbox-button v-for="city in cities" :label="city" :key="city"
        >{{city}}</el-checkbox-button
      >
    </el-checkbox-group>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox-group v-model="checkboxGroup2" size="medium">
      <el-checkbox-button v-for="city in cities" :label="city" :key="city"
        >{{city}}</el-checkbox-button
      >
    </el-checkbox-group>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox-group v-model="checkboxGroup3" size="small">
      <el-checkbox-button
        v-for="city in cities"
        :label="city"
        :disabled="city === 'Beijing'"
        :key="city"
        >{{city}}</el-checkbox-button
      >
    </el-checkbox-group>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox-group v-model="checkboxGroup4" size="mini" disabled>
      <el-checkbox-button v-for="city in cities" :label="city" :key="city"
        >{{city}}</el-checkbox-button
      >
    </el-checkbox-group>
  </div>
</template>
<script>
  const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen']

  export default {
    data() {
      return {
        checkboxGroup1: ['Shanghai'],
        checkboxGroup2: ['Shanghai'],
        checkboxGroup3: ['Shanghai'],
        checkboxGroup4: ['Shanghai'],
        cities: cityOptions,
      }
    },
  }
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

const cityOptions = ['Shanghai', 'Beijing', 'Guangzhou', 'Shenzhen'];

export default defineComponent({
  setup() {
    const state = reactive({
      checkboxGroup1: ['Shanghai'],
      checkboxGroup2: ['Shanghai'],
      checkboxGroup3: ['Shanghai'],
      checkboxGroup4: ['Shanghai'],
      cities: cityOptions,
    });

    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```

:::

### With borders

:::demo The `border` attribute adds a border to Checkboxes.

```html
<template>
  <div>
    <el-checkbox v-model="checked1" label="Option1" border></el-checkbox>
    <el-checkbox v-model="checked2" label="Option2" border></el-checkbox>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox
      v-model="checked3"
      label="Option1"
      border
      size="medium"
    ></el-checkbox>
    <el-checkbox
      v-model="checked4"
      label="Option2"
      border
      size="medium"
    ></el-checkbox>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox-group v-model="checkboxGroup1" size="small">
      <el-checkbox label="Option1" border></el-checkbox>
      <el-checkbox label="Option2" border disabled></el-checkbox>
    </el-checkbox-group>
  </div>
  <div style="margin-top: 20px">
    <el-checkbox-group v-model="checkboxGroup2" size="mini" disabled>
      <el-checkbox label="Option1" border></el-checkbox>
      <el-checkbox label="Option2" border></el-checkbox>
    </el-checkbox-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        checked1: true,
        checked2: false,
        checked3: false,
        checked4: true,
        checkboxGroup1: [],
        checkboxGroup2: [],
      }
    },
  }
</script>
<!--
<setup>

  import { defineComponent, reactive, toRefs } from 'vue';

  export default defineComponent({
    setup() {
      const state = reactive({
        checked1: true,
        checked2: false,
        checked3: false,
        checked4: true,
        checkboxGroup1: [],
        checkboxGroup2: [],
      });

      return {
        ...toRefs(state),
      };
    },
  });

</setup>
-->
```

:::

### Checkbox Attributes

| Attribute             | Description                                               | Type                               | Accepted Values       | Default |
| --------------------- | --------------------------------------------------------- | ---------------------------------- | --------------------- | ------- |
| model-value / v-model | binding value                                             | string / number / boolean          | —                     | —       |
| label                 | value of the Checkbox when used inside a `checkbox-group` | string / number / boolean / object | —                     | —       |
| 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                    | —                     | —       |
| disabled              | whether the Checkbox is disabled                          | boolean                            | —                     | false   |
| border                | whether to add a border around Checkbox                   | boolean                            | —                     | false   |
| size                  | size of the Checkbox                                      | string                             | medium / small / mini | —       |
| name                  | native 'name' attribute                                   | string                             | —                     | —       |
| checked               | if the Checkbox is checked                                | boolean                            | —                     | false   |
| indeterminate         | same as `indeterminate` in native checkbox                | boolean                            | —                     | false   |

### Checkbox Events

| Event Name | Description                             | Parameters        |
| ---------- | --------------------------------------- | ----------------- |
| change     | triggers when the binding value changes | the updated value |

### Checkbox-group Attributes

| Attribute             | Description                                       | Type    | Accepted Values       | Default |
| --------------------- | ------------------------------------------------- | ------- | --------------------- | ------- |
| model-value / v-model | binding value                                     | array   | —                     | —       |
| size                  | size of checkbox                                  | string  | medium / small / mini | —       |
| disabled              | whether the nesting checkboxes are disabled       | boolean | —                     | false   |
| min                   | minimum number of checkbox checked                | number  | —                     | —       |
| max                   | maximum number of checkbox checked                | number  | —                     | —       |
| text-color            | font color when button is active                  | string  | —                     | #ffffff |
| fill                  | border and background color when button is active | string  | —                     | #409EFF |

### Checkbox-group Events

| Event Name | Description                             | Parameters        |
| ---------- | --------------------------------------- | ----------------- |
| change     | triggers when the binding value changes | the updated value |

### Checkbox-button Attributes

| Attribute   | Description                                               | Type                               | Accepted Values | Default |
| ----------- | --------------------------------------------------------- | ---------------------------------- | --------------- | ------- |
| label       | value of the checkbox when used inside a `checkbox-group` | string / number / boolean / object | —               | —       |
| 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                    | —               | —       |
| disabled    | whether the checkbox is disabled                          | boolean                            | —               | false   |
| name        | native 'name' attribute                                   | string                             | —               | —       |
| checked     | if the checkbox is checked                                | boolean                            | —               | false   |