# stack

The **\<stack>** component provides a stack container where child components are successively stacked and the latter one overwrites the previous one.

> **NOTE**
>
> This component is supported since API version 4. Updates will be marked with a superscript to indicate their earliest API version.


## Child Components

Supported


## Attributes

| Name| Type| Default Value| Mandatory| Description|
| -------- | -------- | -------- | -------- | -------- |
| id | string | - | No| Unique ID of the component.|
| style | string | - | No| Style declaration of the component.|
| class | string | - | No| Style class of the component, which is used to refer to a style table.|
| ref | string | - | No| Reference information of child elements, which is registered with the parent component on **$refs**.|


## Events

| Name| Parameter| Description|
| -------- | -------- | -------- |
| click | - | Triggered when the component is clicked.|
| longpress | - | Triggered when the component is long pressed.|
| swipe<sup>5+</sup> | [SwipeEvent](js-common-events.md) | Triggered when a user quickly swipes on the component.|


## Styles

| Name| Type| Default Value| Mandatory| Description|
| -------- | -------- | -------- | -------- | -------- |
| width | &lt;length&gt; \| &lt;percentage&gt;<sup>5+</sup> | - | No| Component width.<br>If this attribute is not set, the default value **0** is used. |
| height | &lt;length&gt; \| &lt;percentage&gt;<sup>5+</sup> | - | No| Component height.<br>If this attribute is not set, the default value **0** is used. |
| padding | &lt;length&gt; | 0 | No| Shorthand attribute to set the padding for all sides.<br>The attribute can have one to four values:<br>- If you set only one value, it specifies the padding for all the four sides.<br>- If you set two values, the first value specifies the top and bottom padding, and the second value specifies the left and right padding.<br>- If you set three values, the first value specifies the top padding, the second value specifies the left and right padding, and the third value specifies the bottom padding.<br>- If you set four values, they respectively specify the padding for top, right, bottom, and left sides (in clockwise order).|
| padding-[left\|top\|right\|bottom] | &lt;length&gt; | 0 | No| Left, top, right, and bottom padding.|
| margin | &lt;length&gt; \| &lt;percentage&gt;<sup>5+</sup> | 0 | No| Shorthand attribute to set the margin for all sides. The attribute can have one to four values:<br>- If you set only one value, it specifies the margin for all the four sides.<br>- If you set two values, the first value specifies the top and bottom margins, and the second value specifies the left and right margins.<br>- If you set three values, the first value specifies the top margin, the second value specifies the left and right margins, and the third value specifies the bottom margin.<br>- If you set four values, they respectively specify the margin for top, right, bottom, and left sides (in clockwise order).|
| margin-[left\|top\|right\|bottom] | &lt;length&gt; \| &lt;percentage&gt;<sup>5+</sup> | 0 | No| Left, top, right, and bottom margins.|
| border-width | &lt;length&gt; | 0 | No| Shorthand attribute to set the margin for all sides.|
| border-color | &lt;color&gt; | black | No| Shorthand attribute to set the color for all borders.|
| border-radius | &lt;length&gt; | - | No| Radius of round-corner borders.|
| background-color | &lt;color&gt; | - | No| Background color.|
| opacity<sup>5+</sup> | number | 1 | No| Opacity of an element. The value ranges from **0** to **1**. The value **1** means opaque, and **0** means completely transparent.|
| display | string | flex | No| How and whether to display the box containing an element. Available values are as follows:<br>- **flex**: flexible layout<br>- **none**: not rendered|
| [left\|top] | &lt;length&gt; \| &lt;percentage&gt;<sup>6+</sup> | - | No| Edge of the element.<br>- **left**: left edge position of the element. This attribute defines the offset between the left edge of the margin area of a positioned element and left edge of its containing block.<br>- **top**: top edge position of the element. This attribute defines the offset between the top edge of a positioned element and that of a block included in the element. |

> **NOTE**
>
> The absolute positioning does not support a percentage. Therefore, **margin** cannot be set for the child components of the **\<stack>** component.


## Example


```html
<!-- xxx.hml -->
<stack class="stack-parent">
  <div class="back-child bd-radius"></div>
  <div class="positioned-child bd-radius"></div>
  <div class="front-child bd-radius"></div>
</stack>
```


```css
/* xxx.css */
.stack-parent {
  width: 400px;
  height: 400px;
  background-color: #ffffff;
  border-width: 1px;
  border-style: solid;
}
.back-child {
  width: 300px;
  height: 300px;
  background-color: #3f56ea;
}
.front-child {
  width: 100px;
  height: 100px;
  background-color: #00bfc9;
}
.positioned-child {
  width: 100px;
  height: 100px;
  left: 50px;
  top: 50px;
  background-color: #47cc47;
}
.bd-radius {
  border-radius: 16px;
}
```

![en-us_image_0000001380789188](figures/en-us_image_0000001380789188.png)