The .slideToggle() method animates the height of the matched elements. This causes lower parts of the page to slide up or down, appearing to reveal or conceal the items. If the element is initially displayed, it will be hidden; if hidden, it will be shown. The display property is saved and restored as needed. If an element has a display value of inline, then is hidden and shown, it will once again be displayed inline. When the height reaches 0 after a hiding animation, the display style property is set to none to ensure that the element no longer affects the layout of the page.

Durations are given in milliseconds; higher values indicate slower animations, not faster ones. The strings 'fast' and 'slow' can be supplied to indicate durations of 200 and 600 milliseconds, respectively.

We can animate any element, such as a simple image:

<div id="clickme">
  Click here
</div>
<img id="book" src="book.png" alt="" width="100" height="123" />

We will cause .slideToggle() to be called when another element is clicked:

$('#clickme').click(function() {
  $('#book').slideToggle('slow', function() {
    // Animation complete.
  });
});

With the element initially shown, we can hide it slowly with the first click:

A second click will show the element once again:

Easing

As of jQuery 1.4.3, an optional string naming an easing function may be used. Easing functions specify the speed at which the animation progresses at different points within the animation. The only easing implementations in the jQuery library are the default, called swing, and one that progresses at a constant pace, called linear. More easing functions are available with the use of plug-ins, most notably the jQuery UI suite.

Callback Function

If supplied, the callback is fired once the animation is complete. This can be useful for stringing different animations together in sequence. The callback is not sent any arguments, but this is set to the DOM element being animated. If multiple elements are animated, it is important to note that the callback is executed once per matched element, not once for the animation as a whole.

As of jQuery 1.6, the .promise() method can be used in conjunction with the deferred.done() method to execute a single callback for the animation as a whole when all matching elements have completed their animations ( See the example for .promise() ).

• All jQuery effects, including .slideToggle(), can be turned off globally by setting jQuery.fx.off = true, which effectively sets the duration to 0. For more information, see jQuery.fx.off.
• Because of the nature of requestAnimationFrame(), you should never queue animations using a setInterval or setTimeout loop. In order to preserve CPU resources, browsers that support requestAnimationFrame will not update animations when the window/tab is not displayed. If you continue to queue animations via setInterval or setTimeout while animation is paused, all of the queued animations will begin playing when the window/tab regains focus. To avoid this potential problem, use the callback of your last animation in the loop, or append a function to the elements .queue() to set the timeout to start the next animation.