scroll-margin - CSS: Cascading Style Sheets 编辑

The scroll-margin shorthand property sets all of the scroll margins of an element at once, assigning values much like the margin property does for margins of an element.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Constituent properties

This property is a shorthand for the following CSS properties:

• scroll-margin-bottom
• scroll-margin-left
• scroll-margin-right
• scroll-margin-top

Syntax

/* <length> values */
scroll-margin: 10px;
scroll-margin: 1em .5em 1em 1em;

/* Global values */
scroll-margin: inherit;
scroll-margin: initial;
scroll-margin: unset;

Values

<length>

An outset from the corresponding edge of the scroll container.

Description

You can see the effect of scroll-margin by scrolling to a point partway between two of the "pages" of the example's content. The value specified for scroll-margin determines how much of the page that's primarily outside the snapport should remain visible.

Thus, the scroll-margin values represent outsets defining the scroll snap area that is used for snapping this box to the snapport. The scroll snap area is determined by taking the transformed border box, finding its rectangular bounding box (axis-aligned in the scroll container’s coordinate space), then adding the specified outsets.

Formal definition

Formal syntax

<length>{1,4}

Examples

Simple demonstration

This example implements something very similar to the interactive example above, except that here we'll explain to you how it's implemented.

The aim here is to create four horizontally-scrolling blocks, the second and third of which snap into place, near but not quite at the left of each block.

HTML

The HTML that represents the blocks is very simple:

<div class="scroller">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
</div>

CSS

Let's walk through the CSS. the outer container is styled like this:

.scroller {
  text-align: left;
  width: 250px;
  height: 250px;
  overflow-x: scroll;
  display: flex;
  box-sizing: border-box;
  border: 1px solid #000;
  scroll-snap-type: x mandatory;
}

The main parts relevant to the scroll snapping are overflow-x: scroll, which makes sure the contents will scroll and not be hidden, and scroll-snap-type: x mandatory, which dictates that scroll snapping must occur along the horizontal axis, and the scrolling will always come to rest on a snap point.

The child elements are styled as follows:

.scroller > div {
  flex: 0 0 250px;
  width: 250px;
  background-color: #663399;
  color: #fff;
  font-size: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  scroll-snap-align: start;
}

.scroller > div:nth-child(2n) {
  background-color: #fff;
  color: #663399;
}

The most relevant part here is scroll-snap-align: start, which specifies that the left-hand edges (the "starts" along the x axis, in our case) are the designated snap points.

Last of all we specify the scroll margin-values, a different one for the second and third child elements:

.scroller > div:nth-child(2) {
  scroll-margin: 1rem;
}

.scroller > div:nth-child(3) {
  scroll-margin: 2rem;
}

This means that when scrolling past the middle child elements, the scrolling will snap to 1rem outside the left edge of the second <div>, and 2rems outside the left edge of the third <div>.

Note: Here we are setting scroll-margin on all sides at once, but only the start edge is really relevant. It would work just as well here to only set a scroll margin on that one edge, for example with scroll-margin-inline-start: 1rem, or scroll-margin: 0 0 0 1rem.

Result

Try it for yourself:

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• CSS Scroll Snap
• Well-Controlled Scrolling with CSS Scroll Snap