function hideLayer(whichLayer) 
{
if (document.getElementById) 
{
// this is the way the standards work
document.getElementById(whichLayer).style.visibility = "hidden";
}
else if (document.all) 
{
// this is the way old msie versions work
document.all[whichlayer].style.visibility = "hidden";
}
else if (document.layers) 
{
// this is the way nn4 works
document.layers[whichLayer].visibility = "hidden";
}
}

function showLayer(whichLayer) 
{
if (document.getElementById) 
{
// this is the way the standards work
document.getElementById(whichLayer).style.visibility = "visible";
}
else if (document.all) 
{
// this is the way old msie versions work
document.all[whichlayer].style.visibility = "visible";
}
else if (document.layers) 
{
// this is the way nn4 works
document.layers[whichLayer].visibility = "visible";
}
}

var chaptervar=0;

function showChapters(number) 
{
	chaptervar = number;
	
	if (number == 1){showLayer("pulldownmenu1");}
	if (number == 2){showLayer("pulldownmenu2");}
	if (number == 3){showLayer("pulldownmenu3");}
}
function hideChapters() 
{
	if (chaptervar == 1){hideLayer("pulldownmenu1");}
	else if (chaptervar == 2){hideLayer("pulldownmenu2");}
	else if (chaptervar == 3){hideLayer("pulldownmenu3");}
	else {}
}