Learn all about the jQuery function .slideDown().
.slideDown() method animates the height of the matched elements. This causes lower parts of the page to slide down, making way for the revealed items.
Durations are given in milliseconds; higher values indicate slower animations, not faster ones. The strings
'slow' can be supplied to indicate durations of
600 milliseconds, respectively. If any other string is supplied, or if the
duration parameter is omitted, the default duration of
400 milliseconds is used.
We can animate any element, such as a simple image:
With the element initially hidden, we can show it slowly:
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.
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() ).