var ns6 = (!document.all && document.getElementById);
var ie4 = (document.all);
var ns4 = (document.layers);
function showLayer(layerName) {
var layerImageName = layerName + "Image"
if (ns6) {
if ( document.getElementById(layerName).style.display == '' ) {
document.getElementById(layerName).style.display = 'none';
} else {
document.getElementById(layerName).style.display = '';
}
} else if (ie4) {
if ( document.all[layerName].style.display == '' ) {
document.all[layerName].style.display = 'none';
} else {
document.all[layerName].style.display = '';
}
} else if (ns4) {
if ( document.layers[layerName].display == '' ) {
document.layers[layerName].display == 'none';
} else {
document.layers[layerName].display == '';
}
}
}