// JavaScript Document

/* 
显示菜单
menuId  菜单div的id
menuButtom  触发显示菜单的按钮对象(可为null)
isLeft 默认从左边对齐 true左边 false右边
*/
function showMenu(menuId,menuButtom,isLeft){
	var menuObj=document.getElementById(menuId);
	if(menuButtom!=null){
		var ttop  = menuButtom.offsetTop+menuButtom.clientHeight;
		var tleft = menuButtom.offsetLeft; 
		var cleft=menuObj.offsetWidth-menuButtom.offsetWidth; //差值
		while (menuButtom = menuButtom.offsetParent){
			ttop+=menuButtom.offsetTop; 
			tleft+=menuButtom.offsetLeft;
		}
		isLeft=isLeft==null?true:isLeft;
		menuObj.style.top  =ttop+"px";
		menuObj.style.left = (isLeft?tleft:tleft-cleft)+"px";
	}
	menuObj.style.visibility="visible";
}

/* 
隐藏菜单 
menuId  菜单div的id
*/
function hiddenMenu(menuId){
	menuObj=document.getElementById(menuId);
	menuObj.style.visibility="hidden";
}