function HideSecondLevelMenus()
//	hides second level menus
{
if (document.all)
	window.document.all.opleidingen.style.visibility='hidden'
else
	if (document.getElementById)
		window.document.getElementById("opleidingen").style.visibility='hidden'

HideThirdLevelMenus()	
}

function HideThirdLevelMenus()
//	hides third level menus
{
if (document.all)
	window.document.all.windows.style.visibility='hidden'
	window.document.all.linux.style.visibility='hidden'
	window.document.all.mac.style.visibility='hidden'
	window.document.all.unix.style.visibility='hidden'
	window.document.all.office.style.visibility='hidden'
	window.document.all.corel.style.visibility='hidden'
	window.document.all.lotus.style.visibility='hidden'
	window.document.all.internet.style.visibility='hidden'
	window.document.all.webdesign.style.visibility='hidden'
	window.document.all.adobe.style.visibility='hidden'
	window.document.all.divers.style.visibility='hidden'
}

function ShowMenu(sLayer)
//	shows the specified layer
{
if (document.all)
	eval("window.document.all."+sLayer+".style.visibility='visible'")
}

function handleError()
{
	return true;
}

//    script body
//window.onerror=handleError