jQuery Tutorial plus Question:

In jQuery we have three methods to give the fade effect to elements: fadeIn, fadeOut and fadeTo
This methods change the opacity of element with animation.

Syntax:
$(selector).fadeIn(speed,callback)
$(selector).fadeOut(speed,callback)
$(selector).fadeTo(speed,opacity,callback)

"speed" can be one of following values : "slow", "fast", "normal" or milliseconds
"opacity" specify the value that allows the fading to given opacity.
"callback" is the function which we want to run once the fading effect is complete.
For example

$("clickme").click(function(){
$("mydiv").fadeTo("slow",0.50);
});

$("clickme").click(function(){
$("mydiv").fadeOut(3000);
});.