ns4 = (document.layers)? true:false
ie4 = (document.all)? true:false
nn6 = (!document.all && document.getElementById)

function show(id){
if (ns4) document.layers[id].visibility = "show"
else
if (ie4) document.all[id].style.visibility = "visible"
else
if (nn6) document.getElementById(id).style.visibility="visible"
}

function hide(id){
if (ns4) document.layers[id].visibility = "hide"
else
if (ie4) document.all[id].style.visibility = "hidden"
else
if (nn6) document.getElementById(id).style.visibility="hidden"
}