function ocultar_capa (capa, fr)
{
	document.getElementById('div_'+capa).style.display = "none";
	if (fr == "si") document.getElementById('fr_'+capa).src = "";
}
	
function mostrar_capa (capa, url, valor) {
	if(valor == "si") {	
		document.getElementById('div_'+capa).style.display = 'none';
		document.getElementById('div_'+capa).style.position = 'absolute';
		document.getElementById('div_'+capa).style.top = "50%";
	
//		document.getElementById('div_'+capa).style.position = 'fixed';
//		document.getElementById('div_'+capa).style.top = document.documentElement.clientHeight/2 - document.getElementById('div_'+capa).offsetHeight/2;
	
		document.getElementById('div_'+capa).style.display = "block";
		if (url != "") document.getElementById('fr_'+capa).src = url;
	}
}