function controlaCamada(banner) 
{ 
    if( document.getElementById(banner).style.visibility == "hidden" ) 
    { 
        document.getElementById(banner).style.visibility = "visible"; 
    } else 
    { 
        document.getElementById(banner).style.visibility = "hidden"; 
    } 	
	{
		setInterval(showHide, 5000);
	}
}