(function($){  
    $.fn.banner = function() {
       
        var current    = null,
            random     = null,
            previous   = null,
            banners    = $('#banners .banner'),
            areas      = $('#areas tr');
        
        return this.each(function()
        {
            if (banners.size() > 0)
            {
            	banners.hide();
            	areas.each(function(e)
            	{
					$(this).bind("click", function()
					{
						showBanner(e);
					});
            	});
            	
            	showRandomBanner();
            }
                
			function showRandomBanner()
			{
                if (banners.size() > 1)
                {
                	random = Math.floor(Math.random()*banners.size());
                }
                else
                {
                    random = 0;
                }
                
            	showBanner(random);
            }
            
            function showBanner(current)
            {
                if (current != previous)
                {
                    if (previous != null)
                    {
                        $(banners[previous]).hide();
                        areas[previous].className = '';
                    }
                    
                    areas[current].className = 'selected';
                    $(banners[current]).show();
                    previous = current;
                }
            }
        });
    };
})(jQuery);

$('#banner').banner();