view-timeline CSS property

Constituent properties

This property is a shorthand for the following CSS properties:

• view-timeline-axis
• view-timeline-inset
• view-timeline-name

Syntax

/* One component */
view-timeline: none;
view-timeline: --custom_name_for_timeline;

/* Two components */
view-timeline: --custom_name_for_timeline block;
view-timeline: --custom_name_for_timeline y;
view-timeline: none inline;
view-timeline: none x;

/* Three components */
view-timeline: --custom_name_for_timeline block auto;
view-timeline: --custom_name_for_timeline block 20% 200px;

/* Global values */
view-timeline: inherit;
view-timeline: initial;
view-timeline: revert;
view-timeline: revert-layer;
view-timeline: unset;

Values

<view-timeline-name>

See view-timeline-name. The default value is none.

<view-timeline-inset>

See view-timeline-inset. The default value is auto.

<view-timeline-axis>

See view-timeline-axis. The default value is block.

Description

The view-timeline shorthand property defines a named view progress timeline, which progresses based on changes to the visibility of an element (the subject) within a scrollable element (scroller). The view-timeline property is set on the subject. If the scroller element does not overflow its container in the axis dimension or if the overflow is hidden or clipped, no scroll progress timeline will be created.

The subject's visibility inside the scroller is tracked — by default, the timeline is at 0% when the subject is first visible at one edge of the scroller and 100% when it reaches the opposite edge.

The view-timeline can contain three constituent values: a name for the named view progress timeline, a scroll axis value, and up to two timeline inset values. If only one value is declared, the value is the view-timeline-name. The name is then referenced in an animation-timeline declaration to indicate the element that will be animated as the timeline progresses. This can be the subject element, but it doesn't have to be — you can animate a different element as the subject moves through the scrolling area.

The view-timeline shorthand property can be applied to a container element to set a combination of the <view-timeline-name>, <view-timeline-inset>, and <view-timeline-axis> values. At least one value must be specified. If all values are specified, the order must be <view-timeline-name> followed by <view-timeline-axis> and/or <view-timeline-inset>.

The names specified in the <view-timeline-name> component must be a list of comma-separated <dashed-ident> values (which means they must start with --) or the keyword none.

Formal definition

Formal syntax

view-timeline = 
  [ <'view-timeline-name'> [ <'view-timeline-axis'> || <'view-timeline-inset'> ]? ]#  

<view-timeline-name> = 
  [ none | <dashed-ident> ]#  

<view-timeline-axis> = 
  [ block | inline | x | y ]#  

<view-timeline-inset> = 
  [ [ auto | <length-percentage> ]{1,2} ]#  

<length-percentage> = 
  <length>      |
  <percentage>  

Examples

Creating a named view progress timeline

A view progress timeline named --subject-reveal is defined using the view-timeline property on a subject element with a class of animation. This is then set as the timeline for the same element using animation-timeline: --subject-reveal. The result is that the subject element animates as it moves upwards through the document as it is scrolled.

HTML

The HTML for the example is shown below.

<div class="content">
  <h1>Content</h1>

  <p>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
    tempor incididunt ut labore et dolore magna aliqua. Risus quis varius quam
    quisque id. Et ligula ullamcorper malesuada proin libero nunc consequat
    interdum varius. Elit ullamcorper dignissim cras tincidunt lobortis feugiat
    vivamus at augue.
  </p>

  <p>
    Dolor sed viverra ipsum nunc aliquet. Sed sed risus pretium quam vulputate
    dignissim. Tortor aliquam nulla facilisi cras. A erat nam at lectus urna
    duis convallis convallis. Nibh ipsum consequat nisl vel pretium lectus.
    Sagittis aliquam malesuada bibendum arcu vitae elementum. Malesuada bibendum
    arcu vitae elementum curabitur vitae nunc sed velit.
  </p>

  <div class="subject animation"></div>

  <p>
    Adipiscing enim eu turpis egestas pretium aenean pharetra magna ac. Arcu
    cursus vitae congue mauris rhoncus aenean vel. Sit amet cursus sit amet
    dictum. Augue neque gravida in fermentum et. Gravida rutrum quisque non
    tellus orci ac auctor augue mauris. Risus quis varius quam quisque id diam
    vel quam elementum. Nibh praesent tristique magna sit amet purus gravida
    quis. Duis ultricies lacus sed turpis tincidunt id aliquet. In egestas erat
    imperdiet sed euismod nisi. Eget egestas purus viverra accumsan in nisl nisi
    scelerisque. Netus et malesuada fames ac.
  </p>
</div>

CSS

The subject element and its containing content element are styled minimally, and the text content is given some basic font settings:

.subject {
  width: 300px;
  height: 200px;
  margin: 0 auto;
  background-color: deeppink;
}

.content {
  width: 75%;
  max-width: 800px;
  margin: 0 auto;
}

p,
h1 {
  font-family: "Helvetica", "Arial", sans-serif;
}

h1 {
  font-size: 3rem;
}

p {
  font-size: 1.5rem;
  line-height: 1.5;
}

The <div> with the class of subject is also given a class of animation — this is where view-timeline is set to define a named view progress timeline. It is also given an animation-timeline name with the same value to declare that this will be the element animated as the view progress timeline progresses.

Lastly, an animation is specified on the element that animates its opacity and scale, causing it to fade in and grow as it moves up the scroller.

.animation {
  view-timeline: --subject-reveal block;
  animation-timeline: --subject-reveal;

  animation-name: appear;
  animation-fill-mode: both;
  animation-duration: 1ms; /* Firefox requires this to apply the animation */
}

@keyframes appear {
  from {
    opacity: 0;
    transform: scaleX(0);
  }

  to {
    opacity: 1;
    transform: scaleX(1);
  }
}

@layer no-support {
  @supports not (view-timeline: none) {
    body::before {
      content: "Your browser doesn't support the `view-timeline` property.";
      background-color: wheat;
      display: block;
      text-align: center;
      padding: 1rem 0;
    }
  }
}

Result

Scroll to see the subject element being animated.

Specifications

Browser compatibility

See also

• animation-timeline
• view-timeline-axis, view-timeline-inset, view-timeline-name
• view()
• Guide: CSS scroll driven animation timelines
• CSS scroll-driven animations