$(document).ready(function() {	

  //Get all the LI from the #tabMenu UL
  $('#tabMenu > li').click(function()
  {
    //perform the actions when it's not selected
    if (!$(this).hasClass('selected')) 
    {    

    //remove the selected class from all LI    
    $('#tabMenu > li').removeClass('selected');
    
    //After cleared all the LI, reassign the class to the selected tab
    $(this).addClass('selected');
    
    //Hide all the DIV in .boxBody
    $('.boxBody div').slideUp('1500');
    
    //Look for the right DIV index based on the Navigation UL index
    $('.boxBody div:eq(' + $('#tabMenu > li').index(this) + ')').slideDown('1500');
    }
   });
	
});