var isDOM = (document.getElementById ? true : false); 
	var isIE4 = ((document.all && !isDOM) ? true : false);
	var isNS4 = (document.layers ? true : false);


	function getRef(id) {
		if (isDOM) return document.getElementById(id);
		if (isIE4) return document.all[id];
		if (isNS4) return document.layers[id];
	}


	function getSty(id) {
		return (isNS4 ? getRef(id) : getRef(id).style);
	} 

	// Hide timeout.
	var popTimer = 0;

	// Array showing highlighted menu items.
	var litNow = new Array();

	function popOver(menuNum, itemNum) {
		clearTimeout(popTimer);
		hideAllBut(menuNum);
		litNow = getTree(menuNum, itemNum);
		changeCol(litNow, true);
		targetNum = menu[menuNum][itemNum].target;
		if (targetNum > 0) {
			thisX = parseInt(menu[menuNum][0].ref.left) + parseInt(menu[menuNum][itemNum].ref.left);
			thisY = parseInt(menu[menuNum][0].ref.top) + parseInt(menu[menuNum][itemNum].ref.top);
			with (menu[targetNum][0].ref) {
				left = parseInt(thisX + menu[targetNum][0].x);
				top = parseInt(thisY + menu[targetNum][0].y);
				visibility = 'visible';
			}
		}
	}


	function popOut(menuNum, itemNum) {
		if ((menuNum == 0) && !menu[menuNum][itemNum].target)
			hideAllBut(0)
		else
			popTimer = setTimeout('hideAllBut(0)', 500);
	}


	function getTree(menuNum, itemNum) {

	// Array index is the menu number. The contents are null (if that menu is not a parent)
	// or the item number in that menu that is an ancestor (to light it up).
	itemArray = new Array(menu.length);

		while(1) {
			itemArray[menuNum] = itemNum;
			// If we've reached the top of the hierarchy, return.
			if (menuNum == 0) return itemArray;
			itemNum = menu[menuNum][0].parentItem;
			menuNum = menu[menuNum][0].parentMenu;
		}
		return true;
	}

	// Pass an array and a boolean to specify colour change, true = over colour.
	function changeCol(changeArray, isOver) {
		for (menuCount = 0; menuCount < changeArray.length; menuCount++) {
			if (changeArray[menuCount]) {
				newCol = isOver ? menu[menuCount][0].overCol : menu[menuCount][0].backCol;
				// Change the colours of the div/layer background.
				with (menu[menuCount][changeArray[menuCount]].ref) {
					if (isNS4) bgColor = newCol;
					else backgroundColor = newCol;
				}
			}
		}
	}


	function hideAllBut(menuNum) {
		var keepMenus = getTree(menuNum, 1);
		for (count = 0; count < menu.length; count++)
		if (!keepMenus[count])
		menu[count][0].ref.visibility = 'hidden';
		changeCol(litNow, false);
	}


	// *** MENU CONSTRUCTION FUNCTIONS ***

	function Menu(isVert, popInd, x, y, width, overCol, backCol, borderClass, textClass) {
		// True or false - a vertical menu?
		this.isVert = isVert;
		// The popout indicator used (if any) for this menu.
		this.popInd = popInd
		// Position and size settings.
		this.x = x;
		this.y = y;
		this.width = width;
		// Colours of menu and items.
		this.overCol = overCol;
		this.backCol = backCol;
		// The stylesheet class used for item borders and the text within items.
		this.borderClass = borderClass;
		this.textClass = textClass;
		// Parent menu and item numbers, indexed later.
		this.parentMenu = null;
		this.parentItem = null;
		// Reference to the object's style properties (set later).
		this.ref = null;
	}

	function Item(text, href, frame, length, spacing, target) {
		this.text = text;
		this.href = href;
		this.frame = frame;
		this.length = length;
		this.spacing = spacing;
		this.target = target;
		// Reference to the object's style properties (set later).
		this.ref = null;
	}

	function writeMenus() {
		if (!isDOM && !isIE4 && !isNS4) return;

		for (currMenu = 0; currMenu < menu.length; currMenu++) with (menu[currMenu][0]) {
			// Variable for holding HTML for items and positions of next item.
			var str = '', itemX = 0, itemY = 0;

			// Remember, items start from 1 in the array (0 is menu object itself, above).
			// Also use properties of each item nested in the other with() for construction.
			for (currItem = 1; currItem < menu[currMenu].length; currItem++) with (menu[currMenu][currItem]) {
				var itemID = 'menu' + currMenu + 'item' + currItem;

				// The width and height of the menu item - dependent on orientation!
				var w = (isVert ? width : length);
				var h = (isVert ? length : width);

				// Create a div or layer text string with appropriate styles/properties.
				// Thanks to Paul Maden (www.paulmaden.com) for helping debug this in IE4, apparently
				// the width must be a miniumum of 3 for it to work in that browser.
				if (isDOM || isIE4) {
					str += '<div id="' + itemID + '" style="position: absolute; left: ' + itemX + '; top: ' + itemY + '; width: ' + w + '; height: ' + h + '; visibility: inherit; ';
					if (backCol) str += 'background: ' + backCol + '; ';
					str += '" ';
				}
				if (isNS4) {
					str += '<layer id="' + itemID + '" left="' + itemX + '" top="' + itemY + '" width="' +  w + '" height="' + h + '" visibility="inherit" ';
					if (backCol) str += 'bgcolor="' + backCol + '" ';
				}
				if (borderClass) str += 'class="' + borderClass + '" ';

				// Add mouseover handlers and finish div/layer.
				str += 'onMouseOver="popOver(' + currMenu + ',' + currItem + ')" onMouseOut="popOut(' + currMenu + ',' + currItem + ')">';

				// Add contents of item (default: table with link inside).
				// In IE/NS6+, add padding if there's a border to emulate NS4's layer padding.
				// If a target frame is specified, also add that to the <a> tag.

				str += '<table width="' + (w - 8) + '" border="0" cellspacing="0" cellpadding="' + (!isNS4 && borderClass ? 3 : 0) + '"><tr><td align="left" height="' + (h - 7) + '">' + '<a class="' + textClass + '" href="' + href + '"' + (frame ? ' target="' + frame + '">' : '>') + text + '</a></td>';
				if (target > 0) {

					// Set target's parents to this menu item.
					menu[target][0].parentMenu = currMenu;
					menu[target][0].parentItem = currItem;

					// Add a popout indicator.
					if (popInd) str += '<td class="' + textClass + '" align="right">' + popInd + '</td>';
				}
				str += '</tr></table>' + (isNS4 ? '</layer>' : '</div>');
				if (isVert) itemY += length + spacing;
				else itemX += length + spacing;
			}
			if (isDOM) {
				var newDiv = document.createElement('div');
				document.getElementsByTagName('body').item(0).appendChild(newDiv);
				newDiv.innerHTML = str;
				ref = newDiv.style;
				ref.position = 'absolute';
				ref.visibility = 'hidden';
			}

			// Insert a div tag to the end of the BODY with menu HTML in place for IE4.
			if (isIE4) {
				document.body.insertAdjacentHTML('beforeEnd', '<div id="menu' + currMenu + 'div" ' + 'style="position: absolute; visibility: hidden">' + str + '</div>');
				ref = getSty('menu' + currMenu + 'div');
			}

			// In NS4, create a reference to a new layer and write the items to it.
			if (isNS4) {
				ref = new Layer(0);
				ref.document.write(str);
				ref.document.close();
			}

			for (currItem = 1; currItem < menu[currMenu].length; currItem++) {
				itemName = 'menu' + currMenu + 'item' + currItem;
				if (isDOM || isIE4) menu[currMenu][currItem].ref = getSty(itemName);
				if (isNS4) menu[currMenu][currItem].ref = ref.document[itemName];
			}
		}

		with(menu[0][0]) {
			ref.left = x;
			ref.top = y;
			ref.visibility = 'visible';
   		}
	}

	// *** OPTIONAL CODE FROM HERE DOWN ***

	// These two lines handle the window resize bug in NS4. See <body onResize="...">.
	// I recommend you leave this here as otherwise when you resize NS4's width menus are hidden.

	var popOldWidth = window.innerWidth;
	nsResizeHandler = new Function('if (popOldWidth != window.innerWidth) location.reload()');


	// This is a quick snippet that captures all clicks on the document and hides the menus
	// every time you click. Use if you want.

	if (isNS4) document.captureEvents(Event.CLICK);
	document.onclick = clickHandle;

	function clickHandle(evt) {
		if (isNS4) document.routeEvent(evt);
		hideAllBut(0);
	}


	// This is just the moving command for the example.

	function moveRoot() {
		with(menu[0][0].ref) left = ((parseInt(left) < 100) ? 100 : 5);
	}