Tween

Description

(Optional) Specify the animation tween setting. If you leave this blank, the default tween is used.

Discussion

The Tween property defines the transition timing for when the disclosure is shown or hidden. You can specify any timing value that is supported by the CSS transition-timing-function property, including the following:

ease
ease-in
ease-out
ease-in-out
linear
step-start
step-end

You can also use a CSS timing function to define custom transition timing:

steps(<integer>,[start|end])
cubic-bezier(<number>,<number>,<number>,<number>)
frames(<integer>)

cubic-bezier(0.68, -0.55, 0.265, 1.55)

See Using CSS transitions to learn more.