var timeout	= 500;
var closetimer	= 0;
var ddmenuitem	= 0;

function mopen(id) {	
	mcancelclosetime();
	if(ddmenuitem) {
		ddmenuitem.style.visibility = 'hidden';
	}
	ddmenuitem = document.getElementById(id);
	ddmenuitem.style.visibility = 'visible';

}
function mclose() {
	if(ddmenuitem) {
		ddmenuitem.style.visibility = 'hidden';
	}
}
function mclosetime() {
	closetimer = window.setTimeout(mclose, timeout);
}
function mcancelclosetime() {
	if(closetimer) {
		window.clearTimeout(closetimer);
		closetimer = null;
	}
}
document.onclick = mclose;