function MostrarCapa(capa){
  if(document.layers)document.layers[capa].visibility='show'
  if(document.all)document.all(capa).style.visibility='visible'
}

function OcultarCapa(capa){
  if(document.layers)document.layers[capa].visibility='hide'
  if(document.all)document.all(capa).style.visibility='hidden'
}