overscroll-behavior
===================

The **`overscroll-behavior`** CSS property sets what a browser does when reaching the boundary of a scrolling area.

Try it
------

Constituent properties
----------------------

This property is a shorthand for the following CSS properties:

* `overscroll-behavior-x`
* `overscroll-behavior-y`
Syntax
------


```css
/\* Keyword values \*/
overscroll-behavior: auto; /\* default \*/
overscroll-behavior: contain;
overscroll-behavior: none;

/\* Two values \*/
overscroll-behavior: auto contain;

/\* Global values \*/
overscroll-behavior: inherit;
overscroll-behavior: initial;
overscroll-behavior: revert;
overscroll-behavior: revert-layer;
overscroll-behavior: unset;
```


The `overscroll-behavior` property is specified as one or two keywords chosen from the list of values below.

Two keywords specifies the `overscroll-behavior` value on the `x` and `y` axes respectively. If only one value is specified, both x and y are assumed to have the same value.

### Values

`auto`

The default scroll overflow behavior occurs as normal.

`contain`

Default scroll overflow behavior (e.g., "bounce" effects) is observed inside the element where this value is set. However, no scroll chaining occurs on neighboring scrolling areas; the underlying elements will not scroll. The `contain` value disables native browser navigation, including the vertical pull-to-refresh gesture and horizontal swipe navigation.

`none`

No scroll chaining occurs to neighboring scrolling areas, and default scroll overflow behavior is prevented.

Description
-----------

By default, mobile browsers tend to provide a "bounce" effect or even a page refresh when the top or bottom of a page (or other scroll area) is reached. You may also have noticed that when you have a dialog box with scrolling content at the top of a page that also has scrolling content, once the dialog box's scroll boundary is reached, the underlying page will then start to scroll — this is called scroll chaining.

In some cases, these behaviors are not desirable. You can use `overscroll-behavior` to get rid of unwanted scroll chaining and the browser's Facebook/Twitter app-inspired "pull to refresh"-type behavior.

Note that this property applies only to scroll containers. In particular, since an `<iframe>` is not a scroll container, setting this property on an iframe has no effect. To control scroll chaining from an iframe, set `overscroll-behavior` on both the `<html>` and the `<body>` elements of the iframe's document.

Formal definition
-----------------

|  |  |
| --- | --- |
| Initial value | `auto` |
| Applies to | non-replaced block-level elements and non-replaced inline-block elements |
| Inherited | no |
| Computed value | as each of the properties of the shorthand:* `overscroll-behavior-x`: as specified
* `overscroll-behavior-y`: as specified
 |
| Animation type | discrete |

Formal syntax
-------------
```

overscroll-behavior =   
  [ contain | none | auto ]{1,2}    
  
```

Examples
--------

### Preventing an underlying element from scrolling

In our overscroll-behavior example (see the source code also), we present a full-page list of fake contacts, and a dialog box containing a chat window.

![A popup chat window titled 'Active chat', showing a conversation between Chris and Bob. Behind the chat window is a contact list titled 'overscroll-behavior demo'.](/en-US/docs/Web/CSS/overscroll-behavior/example.png)

Both of these areas scroll; normally if you scrolled the chat window until you hit a scroll boundary, the underlying contacts window would start to scroll too, which is not desirable. This can be stopped using `overscroll-behavior-y` (`overscroll-behavior` would also work) on the chat window, like this:


```css
.messages {
  height: 220px;
  overflow: auto;
  overscroll-behavior-y: contain;
}
```


We also wanted to get rid of the standard overscroll effects when the contacts are scrolled to the top or bottom (e.g. Chrome on Android refreshes the page when you scroll past the top boundary). This can be prevented by setting `overscroll-behavior: none` on the `<html>` element:


```css
html {
  margin: 0;
  overscroll-behavior: none;
}
```

Specifications
--------------

| Specification |
| --- |
| CSS Overscroll Behavior Module Level 1 # overscroll-behavior-properties |

Browser compatibility
---------------------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

See also
--------

* Take control of your scroll: customizing pull-to-refresh and overflow effects on developer.chrome.com (2017)