// Funciones genericas para mostrar y ocultar capas.
function changedisp(whatdiv,whatdisp,whatcover)
{
	if (whatcover=='') {document.getElementById(whatdiv).style.display=whatdisp}
	else
	{
		if (whatdisp=='') document.getElementById(whatdiv).style.display='';
		else document.getElementById(whatdiv).style.display='none';
	}
}
function checker(whatcheck,whatblock)
{
	if (document.getElementById(whatcheck).checked==true) changedisp(whatblock,'none','')
	else changedisp(whatblock,'','')
}

function alternatedisp(whatdiv)
{
        if(document.getElementById(whatdiv).style.display == "none")
        {
                document.getElementById(whatdiv).style.display = "";
        }
    else document.getElementById(whatdiv).style.display = "none";
}