function show_banner()
	{
                w = (window.screen.width / 2) - (340 / 2);
                h = (window.screen.height / 2) - (435 / 2);
      	    window.open('banners/banner.html','banner','toolbar=0, location=0,directories=0, menubar=0, scrollbars=0, resizable=0, width=340, height=435, left='+w+', top='+h+'');
	}