$(document).ready(function() {	
  $('#tabMenu > li').click(function(){
    if (!$(this).hasClass('selected')) {    
			$('#tabMenu > li').removeClass('selected');
			$(this).addClass('selected');
			$('.boxBody div').slideUp('1500');
			
			//Look for the right DIV in boxBody according to the Navigation UL index, therefore, the arrangement is very important.
			$('.boxBody div:eq(' + $('#tabMenu > li').index(this) + ')').slideDown('1500');
		}
  }).mouseover(function() {
    $(this).addClass('mouseover');
    $(this).removeClass('mouseout');   
  }).mouseout(function() {
    $(this).addClass('mouseout');
    $(this).removeClass('mouseover');
  });
});