$(document).ready(setupTabs);

function setupTabs(){
 $('#mainPanel ul li a').each(
    function(){
      $(this).hover(
        function(){
          swapContent($(this).parent().attr('id'));
        }
      );
    }
  );
}

function swapContent(id){
  //console.log(id);
   $('#mainPanel .content').hide();
   $('#content-' + id).show();
   
   //a#welcome a.currently_selected {}
   
   $('#mainPanel ul li a.currently_selected').removeClass('currently_selected');
   $('#' + id + ' a').addClass('currently_selected');
   
}