size = window.screen.width;

	if (size >= 1900)
		size = 1900
	else if (size > 1400)
		size = 1600
	else 
		size = 1280;
		
	document.write ('<style>body{background-image: url(http://www.accesoxbox.com/img/wall/wall_'+size+'.jpg); background-position: top; background-attachment: fixed; background-repeat: no-repeat;}</style>')