var browserType; 
if (document.layers) {browserType = "nn4"} 
if (document.all) {browserType = "ie"} 
if (window.navigator.userAgent.toLowerCase().match("gecko")
) 
{ browserType= "gecko" } function hide() 
{ if (browserType == "gecko" ) document.poppedLayer = eval('document.getElementById("MainDiv")'); 
else if (browserType == "ie") document.poppedLayer = eval('document.getElementById("MainDiv")'); 
else document.poppedLayer = eval('document.layers["MainDiv"]'); 
document.poppedLayer.style.visibility = "hidden"; 
} 
function show() { if (browserType == "gecko" ) document.poppedLayer = eval('document.getElementById("MainDiv")'); 
else if (browserType == "ie") document.poppedLayer = eval('document.getElementById("MainDiv")'); 
else document.poppedLayer = eval('document.layers["MainDiv"]'); 
document.poppedLayer.style.visibility = "visible"; }