var menuEnCours=0;
//menu functions
function switchMenu(id) {
	//resetMenu(false);
	//set selected menu
	var menu = document.getElementById("menu_"+id);
	setMenu(id, getElementTop(menu) + parseInt(menu.offsetHeight) - 3,  (getElementLeft(menu) + 15), 20, "underline");
	
	menuEnCours = id;
}

function setMenu(id, top, left, zIndex, textDecoration) {
	//get elements
	var menulink = document.getElementById("menulink_"+id);
	var submenu = document.getElementById("submenu_"+id)
	//set styles
	submenu.style.top = top;
	submenu.style.left = left;
	submenu.style.zIndex = zIndex;
	menulink.style.textDecoration = textDecoration;
}

function resetMenu()
{
	var menu = document.getElementById("menu_"+menuEnCours);
	setMenu(menuEnCours, 0 ,  -600, -10, "underline");
}

//get position functions
function getElementTop(element) {
	//getTopPosition
	var e = element;
	var top = e.offsetTop;
	while((e = e.offsetParent) != null) { top += e.offsetTop; }
	//return element top
	return top;
}

function getElementLeft(element) {
	//getLeftPosition
	var e = element;
	var left = e.offsetLeft;
	while((e = e.offsetParent) != null) { left += e.offsetLeft; }
	//return element left
	return left;
}