ns4 = (document.layers)? true:false;
ie4 = (document.all)? true:false;

function hide(id) {
  if (ns4) document.layers[id].visibility = "hide"
  else if (ie4) document.all[id].style.visibility = "hidden"
}

function show(id) {
  if (ns4) document.layers[id].visibility = "show"
  else if (ie4) document.all[id].style.visibility = "visible"
}

function dhide(id) {
  if (ns4) document.layers[id].visibility = "hide"
  else document.all[id].style.display = "none"
}

function dshow(id) {
  if (ns4) document.layers[id].visibility = "show"
  else document.all[id].style.display = "block"
}