jQuery slideDown function shows an element from top to bottom in specified time. slideUp function hides an element from bottom to top in specified interval.
$(element).slideDown(interval, function(){});
$(element).slideUp(interval, function(){});
How does jQuery do it?
jQuery adds several attributes such as “display”,”padding-xxx”, and “margin-xxx” to the element and adjusts their values in the specified interval to realize the animation effects. After slideDown finishes, you can see there added an attrubite in the element: display:block. After slideUp finishes, you can see the attribute becomes: display:none, which actually hides the element.