# 多行输入 Textarea

## 示例
### 基本形式

大部分属性与`<textarea>`元素一致。

``` html
<u-textarea placeholder="Details" autofocus></u-textarea>
```

### 只读与禁用

``` html
<u-linear-layout>
    <u-textarea value="只读" readonly></u-textarea>
    <u-textarea value="禁用" disabled></u-textarea>
</u-linear-layout>
```

### 调整大小

``` html
<u-linear-layout>
    <u-textarea value="none" resize="none"></u-textarea>
    <u-textarea value="horizontal" resize="horizontal"></u-textarea>
    <u-textarea value="vertical" resize="vertical"></u-textarea>
    <u-textarea value="both" resize="both"></u-textarea>
</u-linear-layout>
```

### 大小扩展

```html
<u-linear-layout direction="vertical">
    <u-linear-layout>
        <u-textarea size="normal" value="normal" readonly></u-textarea>
        <u-textarea size="normal large" value="normal large" readonly></u-textarea>
    </u-linear-layout>
    <u-linear-layout>
        <u-textarea size="medium" value="medium" readonly></u-textarea>
    </u-linear-layout>
    <u-linear-layout>
        <u-textarea size="large" value="large" readonly></u-textarea>
    </u-linear-layout>
    <u-linear-layout>
        <u-textarea size="huge" value="huge" readonly></u-textarea>
    </u-linear-layout>
    <u-linear-layout>
        <u-textarea size="huge full" value="huge full" readonly></u-textarea>
    </u-linear-layout>
</u-linear-layout>
```

## API
### Props/Attrs

| Prop/Attr | Type | Default | Description |
| --------- | ---- | ------- | ----------- |
| value | String | | 输入框的值 |
| placeholder | String | | 原生属性 |
| minlength | Number | | 原生属性 |
| maxlength | Number | | 原生属性 |
| autofocus | Boolean | | 原生属性 |
| readonly | Boolean | | 原生属性 |
| disabled | Boolean | | 原生属性 |
| resize | String | | 原生属性 |
| size | String | `'normal'` | 大小扩展，支持一个值：`'normal'`, `'large'`, `'huge'`, `'full'`，或两个值的组合，前者表示高度，后者表示宽度，类似CSS的padding书写格式 |

<!-- | autosize | String | `'none'` | 自适应内容宽高。可选值：`none`、`both`、`horizontal`、`vertical` | -->


### Events
#### @input

输入时触发

| Param | Type | Description |
| ----- | ---- | ----------- |
| $event | String | 输入框的值 |

#### @change

值变化时触发（与原生事件不同）

| Param | Type | Description |
| ----- | ---- | ----------- |
| $event.value | String | 改变后的值 |
| $event.oldValue | String | 旧的值 |

#### @focus

获得焦点时触发

| Param | Type | Description |
| ----- | ---- | ----------- |
| $event | String | 原生事件对象 |

#### @blur

失去焦点时触发

| Param | Type | Description |
| ----- | ---- | ----------- |
| $event | String | 原生事件对象 |