if (navigator.appName == "Netscape") {
        layerRef="document.layers";
        styleSwitch="";
    } else {
        layerRef="document.all";
        styleSwitch=".style";
    }

function showLayer(layerName) {
        eval(layerRef+'["'+layerName+'"]'+styleSwitch+'.visibility="visible"');
}
        
function hideLayer(layerName) {
        eval(layerRef+'["'+layerName+'"]'+styleSwitch+'.visibility="hidden"');
}