/* 
下拉式菜单
引用文件:~\Script\ExplorerUtility.js
*/

var DropDownMenu = new Object();
DropDownMenu.currentSubmenuId = null;

// 显示子菜单
DropDownMenu.show = function(submenuId,menuItem)
{
	var submenu = document.getElementById(submenuId);
	
	if (submenu == null)
	{
		this.currentSubmenuId = "";
		return;
	}		
			
	if (menuItem != null)
	{
		// 子菜单定位
		var left = menuItem.offsetLeft;
		var top = menuItem.offsetTop;
		var obj = menuItem;
		while (obj.offsetParent) 
		{ 
			obj　= obj.offsetParent; 
			left += obj.offsetLeft; 
			top += obj.offsetTop; 
		}
		
		if (ExpUtil.isIE && ExpUtil.isXHTML) {
			top -= 7;
		}
		
		submenu.style.left = left + "px";
		submenu.style.top = top + "px";
	}
	
	this.currentSubmenuId = submenu.id;
	submenu.style.display = "block";
	DropDownMenu.addSubIframe(submenu);
}

// 隐藏子菜单
DropDownMenu.hide = function(submenuId)
{
	this.currentSubmenuId = "";

	var submenu = document.getElementById(submenuId);

	if (submenu == null)
	{
		return;
	}

	window.setTimeout("DropDownMenu.doHide('" + submenu.id + "')",100);
}

// 执行隐藏子菜单
DropDownMenu.doHide = function(submenuId)
{
	var submenu = document.getElementById(submenuId);
	
	if (submenu == null)
	{
		return;
	}

	if (submenu.id != this.currentSubmenuId)
	{
		submenu.style.display = "none";
	}
}

// 标签下添加IFAME,使其不被遮挡。
DropDownMenu.addSubIframe = function(parentTag) {
	var childNodes = parentTag.childNodes;
	var subIframe = null;
	for(i = 0; i < childNodes.length; i++)
	{
		if (childNodes[i].name == "subIframe")
		{
			subIframe = childNodes[i].name;
			break;
		}
	}
	
	if (subIframe == null) {
		subIframe = document.createElement("iframe"); 
		subIframe.src = "javascript:void(0)";
		subIframe.scrolling="no";
		subIframe.style.width = parentTag.offsetWidth + "px";
		subIframe.style.height = parentTag.offsetHeight + "px";	
		ExpUtil.appendChildNode(parentTag,subIframe);
	}
}