overscroll-behavior

Theoverscroll-behaviorCSSproperty sets what a browser does when reaching the boundary of a scrolling area.

Constituent properties

This property is a shorthand for the following CSS properties:

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;

Theoverscroll-behaviorproperty is specified as one or two keywords chosen from the list of values below.

Two keywords specifies theoverscroll-behaviorvalue on thexandyaxes 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. Thecontainvalue 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.

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'sscroll boundaryis reached, the underlying page will then start to scroll — this is calledscroll chaining.

In some cases, these behaviors are not desirable. You can useoverscroll-behaviorto 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 toscroll 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, setoverscroll-behavioron 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 ouroverscroll-behavior example(see thesource codealso), 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'.

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 usingoverscroll-behavior-y(overscroll-behaviorwould 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 settingoverscroll-behavior: noneon 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