JavaScript is a client-side programming language (this means it runs in the browser, not on the server) used to make elements react to user input (such as a click) or events (such as the page loading, or the browser resizing).
$(document).ready(function(){
$('.slideshowFull').cycle({
fx: 'fade' ,
speed: 800,
timeout: 7000
});
});
When you see something move on a website (including fading in or out) it's almost always done with either JavaScript or Flash.