The update CSS media feature can be used to test how frequently (if at all) the output device is able to modify the appearance of content.

Syntax

The update feature is specified as a single keyword value chosen from the list below.

none: Once it has been rendered, the layout can no longer be updated. Example: documents printed on paper.
slow: The layout may change dynamically according to the usual rules of CSS, but the output device is not able to render or display changes quickly enough for them to be perceived as a smooth animation. Examples: e-book readers or severely underpowered devices.
fast: The layout may change dynamically according to the usual rules of CSS, and the output device is not unusually constrained in speed, so regularly-updating things like CSS Animations can be used. Example: computer screens.

CSS

@keyframes jiggle {
  from {
    transform: translateY(0);
  }

  to {
    transform: translateY(25px);
  }
}

@media (update: fast) {
  p {
    animation: 1s jiggle linear alternate infinite;
  }
}

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`update-frequency`	No	No	102	No	No	No	No	No	102	No	No	No

update

Syntax

Examples

HTML

CSS

Result

Specifications

Browser compatibility

See also