var shown = '';
var dom = false;
var base;
var ie5 = false; // IE5 or later
var ie4 = false; // IE4
var ns6 = false; // Netscape 6
var ns4 = false; // Netscape 4
var item = 0;
var top = 7;			//pixels above main menu
var left = 150;			//pixels to left of main menu
var bottom = 50;		//pixels below main menu
var right = 695;		//pixels to right of main menu
ex_top = 27;			//pixels to top of sub menu

if ( (navigator.appName.indexOf("Internet Explorer") > -1) && (parseInt(navigator.appVersion) > 3) ) 
{
	if (navigator.userAgent.indexOf("MSIE 5")!=-1) 
	{
		ie5 = true;
	} 
	else 
	{
		ie4 = true;
	}
} 

if  (navigator.appName.indexOf("Netscape") > -1) 
{
	if (parseInt(navigator.appVersion) >= 5)  
	{
		ns6 = true;
	} 
	else 
	{
		ns4 = true;
	}
}

if (ie5 || ns6) 
{
	dom = true;
} 

if (ns4)
{
	base = 'document.';
	visibility = '.visibility';
}
else if (ie4)
{
	base = 'document.all.';
	visibility = '.style.visibility';
}

if (dom) 
{
	base = "document.getElementById('";
	visibility = "').style.visibility";
}

function showMenu(layer)
{
	if (layer != 'feedback_link')
	{
		hideMenu('feedback_link');
	}
	if (layer != 'home_link')
	{
		hideMenu('home_link');
	}
	if (layer != 'security_link')
	{
		hideMenu('security_link');
	}
	if (layer != 'support_link')
	{
		hideMenu('support_link');
	}
	if (layer != 'corporate_link')
	{
		hideMenu('corporate_link');
	}
	if (layer != 'mobilemail_link')
	{
		hideMenu('mobilemail_link');
	}
	if (layer != 'logout_link')
	{
		hideMenu('logout_link');
	}
	eval(base + layer + visibility + '="visible"');
	shown = layer;
	window.status = layer;
}

function hideMenu(layer)
{
	window.status = '';
	var obj1, obj2, isDom;

	// ----- This is used to check the existence of the object

	if (dom) 
	{
		isDom="')";
	} 
	else 
	{
		isDom="";
	}
	obj1=eval(base + layer + isDom);
	obj2=document.ThisObjectDoesnExist;

	// -----

	if (obj1!=obj2) 
	{
		eval(base + layer + visibility + '="hidden"');
		if (shown == layer)
		{
			shown = '';
		}
	}
}