Jquery fadeIn() Method
fadeIn() method is used to show the hidden element gradually. After applying the
fadeIn() method element opacity is gradually increased from zero to one. Therefore hidden element is shown gradually.
speed: It is an optional parameter. It specifies the speed of the delay of the
fadeIn() method. It has the following values: "slow", "fast" and millisecond.
easing: It specifies the easing function that is used for transition.
callback: It is also an optional parameter. The callback function will be called after the completion of