obj= document.getElementById('mercado');

	switch(screen.width){
		case 800:
			obj.className="body800";
			break;
		case 1024:
			obj.className="body1024";
			break;
		case 1440:
			obj.className="body1440";
			break;
		case 1600:
			obj.className="body1600";
			break;
		default:
			obj.className="body1280";
			break;
	}