var displayRequestCount = 0;
var navIsVisible = false;
var defaultNavKey = null;
var nav1Elems;

function addNavDisplayRequest(key) {
	if (key!=null) setCurrentNav(key);
	displayRequestCount++;
	showNav();
}

function confirmDropShadow() {
	var regex = /MSIE\s(\d)/;
	var match = regex.exec(window.navigator.userAgent);
	if (match==null || parseInt(match[1])<5.5) {
		document.getElementById("dropshadow").style.display="none";
	}
	else {
		document.getElementById("dropshadow").style.display="";
	}
}

function initNav() {
	nav1Elems = eval(document.getElementById("nav1Elems").innerHTML);
	defaultNavKey = eval(document.getElementById("defaultNavKey").innerHTML);
	if (defaultNavKey.length==0) defaultNavKey = null;
	confirmDropShadow();
	showNav();
}

function removeNavDisplayRequest() {
	displayRequestCount--;
	window.setTimeout("showNav();", 500);
}

function setCurrentNav(key) {
	if (nav1Elems==null) return;
	for (var i=0; i<nav1Elems.length; i++) {
		if (nav1Elems[i]==key) {
			document.getElementById("nav1_" + nav1Elems[i]).style.display = "";
		}
		else {
			document.getElementById("nav1_" + nav1Elems[i]).style.display = "none";
		}
	}
}

function setNavVisible(visible) {
	if (visible) {
		if (!navIsVisible) {
			var top = parseInt(titleBar.style.top);
			top += 24;
			titleBar.style.top = top + "px";
			nav1.style.visibility = "visible";
			navIsVisible = true;
		}
	}
	else {
			if (navIsVisible) {
				var top = parseInt(titleBar.style.top);
				top -= 24;
				titleBar.style.top = top + "px";
				nav1.style.visibility = "hidden";
				navIsVisible = false;
			}
	}
}

function showNav() {
	if (window.nav1==null) {
		window.nav1 = document.getElementById("nav1");
	}
	if (window.titleBar==null) {
		window.titleBar = document.getElementById("titleBar");
	}
	if (displayRequestCount>0) {
		setNavVisible(true);
	}
	else {
		if (defaultNavKey!=null) {
			setCurrentNav(defaultNavKey);
			setNavVisible(true);
		}
		else {
			setNavVisible(false);
		}
	}
}