function showhide(layer_ref) {
var state = 'hidden';
var state2 = 'none';
if (document.all) { //IS IE 4 or 5 (or 6 beta)
state =  eval( "document.all." + layer_ref + ".style.visibility");
}
if (document.layers) { //IS NETSCAPE 4 or below
state = document.layers[layer_ref].visibility; 
}
if (document.getElementById && !document.all) {
var el_id = document.getElementById(layer_ref);
state = el_id.style.visibility;

}

if (state == 'visible') {
state = 'hidden';
state2 = 'none';
}
else {
state = 'visible';
state2 = 'block';
}
if (document.all) { //IS IE 4 or 5 (or 6 beta)
eval( "document.all." + layer_ref + ".style.visibility = '" +state +"'");
eval( "document.all." + layer_ref + ".style.display = '" +state2 +"'");
}
if (document.layers) { //IS NETSCAPE 4 or below
document.layers[layer_ref].visibility = state;
document.layers[layer_ref].display = state2;
}
if (document.getElementById && !document.all) {
el_id = document.getElementById(layer_ref);
el_id.style.visibility = state;
el_id.style.display = state2;
}
}