var id='popup';

function hidediv(id) {
//safe function to hide an element with a specified id
if (document.getElementById) { // DOM3 = IE5, NS6 
document.getElementById(id).style.display = 'none';}
else { 
if (document.layers) { // Netscape 4
document.id.display = 'none';}
else { // IE 4
document.all.id.style.display = 'none';}
}
}

function showdiv(id) {
//safe function to show an element with a specified id
if (document.getElementById) { // DOM3 = IE5, NS6
document.getElementById(id).style.display = 'block';}
else {
if (document.layers) { // Netscape 4
document.id.display = 'block';}
else { // IE 4
document.all.id.style.display = 'block';}
}
}