function initMainBanner(timer) {
   $('#mainBanner ul li').css({opacity: 0.0});
   $('#mainBanner ul li:first').css({opacity: 1.0});
   window.setInterval('startMainBanner();', timer);	
}

function startMainBanner() {	
   var current = ($('#mainBanner ul li.show') ? $('#mainBanner ul li.show') : $('#mainBanner ul li:first'));
   var next = ((current.next().length) ? ((current.next().hasClass('show')) ? $('#mainBanner ul li:first') : current.next()) : $('#mainBanner ul li:first'));	
   next.css({opacity: 0.0}).addClass('show').animate({opacity: 1.0}, 1000);
   current.animate({opacity: 0.0}, 1000).removeClass('show');	
}

$(document).ready(function() { initMainBanner(3000); });