function showSubMenu(whichmenu,whichbutton) 
{
if(whichbutton=="about") {
	document.getElementById(whichbutton).src="images/aboutOn.gif";
	} else {
	document.getElementById(whichbutton).src="images/eventsOn.gif";
}
document.getElementById('submenu'+whichmenu).style.visibility="visible";
}



function hideSubMenu(whichmenu,whichbutton) 
{
if(whichbutton=="about") {
	document.getElementById(whichbutton).src="images/about.gif";
	} else {
	document.getElementById(whichbutton).src="images/events.gif";
}
document.getElementById('submenu'+whichmenu).style.visibility="hidden";
}