Effects and duration
When we include a duration (sometimes also referred to as a speed) with
.hide(), it becomes animated—occurring over a specified period of time. The
.hide(duration) method, for example, decreases an element's height, width, and opacity simultaneously until all three reach zero, at which point the CSS rule
display: none is applied. The
.show(duration) method will increase the element's height from top to bottom, width from the left-hand side to the right-hand side, and opacity from 0 to 1 until its contents are completely visible.
With any jQuery effect, we can use one of the two preset speeds,
.show('slow') makes the show effect complete in 600 milliseconds (0.6 seconds),