submenuNo = 0;

function openmenu(){
	closemenu();
	document.getElementById("sub"+submenuNo).style.visibility='visible';
}

function closemenu() {
	timerCount = 0;
	document.getElementById( "sub10" ).style.visibility='hidden';
	document.getElementById( "sub20" ).style.visibility='hidden';
	document.getElementById( "sub30" ).style.visibility='hidden';
}

function getElem(e){
	if(e.target){
		targetNode=e.target;
	}else{
		targetNode=e.srcElement;
	}
	return targetNode;
}

function set10() { submenuNo=10; openmenu(); }
function set20() { submenuNo=20; openmenu(); }
function set30() { submenuNo=30; openmenu(); }

/* エレメントにイベントをセット */
function setListeners(e) {
	var menus = document.getElementById("menus");
	addListener( menus, 'mouseout', closemenu , false );
	addListener( document.getElementById("menu_item10") ,"mouseover", set10 , false );
	addListener( document.getElementById("menu_item20") ,"mouseover", set20 , false );
	addListener( document.getElementById("menu_item30") ,"mouseover", set30 , false );
}

/* イベントリスナをエレメントに登録 */
function addListener(elem,eventType,func,cap){
	if(elem.addEventListener){
		elem.addEventListener( eventType, func, cap );
	}else if(elem.attachEvent){
		elem.attachEvent('on'+eventType,func);
	}
}

addListener( window, 'load', setListeners, false );