will-change

The will-change property hints to the browser which properties are about to change so it can optimize ahead of time.

Since CSS3 Spec ↗

Syntax

will-change: auto | <property>...;  /* e.g. transform, opacity */

Examples

.panel.is-animating {
  will-change: transform, opacity;
}
Output
The browser promotes the panel to its own layer before animation for smoother transforms.

Notes

Use sparingly and only just before an animation; permanent or broad use wastes memory and can hurt performance. Add it via a class right before animating and remove it afterward. It is a hint, not a guarantee.

Browser & runtime support

EnvironmentSince version
chrome 36
firefox 36
safari 9.1
edge 79

See also