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;