var lastMenu = null;

function findPos(obj) {
	var curleft = curtop = 0;
	if (obj.offsetParent) {
		curleft = obj.offsetLeft
		curtop = obj.offsetTop
		while (obj = obj.offsetParent) {
			curleft += obj.offsetLeft
			curtop += obj.offsetTop
		}
	}
	return [curleft,curtop];
}
function swapMenu(obj,menuName) {
	if (lastMenu) {
		document.getElementById(lastMenu).style.visibility = 'hidden';
		document.getElementById(lastMenu).style.display = 'none';
	}
	if (menuName) {
		objPos = findPos(obj);
		menuX = objPos[0]-document.getElementById('contentArea').offsetLeft-1;
		menuY = objPos[1]+obj.offsetHeight-1;

		document.getElementById(menuName).style.marginLeft = menuX+'px';
		document.getElementById(menuName).style.marginTop = menuY+'px';
		document.getElementById(menuName).style.width = obj.offsetWidth;
		document.getElementById(menuName).style.visibility = 'visible';
		document.getElementById(menuName).style.display = 'block';
		document.getElementById(menuName).style.zIndex = 255;
		lastMenu = menuName;
	}

}