/* =================================================================================================
 * TransMenu 
 * March, 2003
 *
 * Customizable multi-level animated DHTML menus with transparency.
 *
 * Copyright 2003-2004, Aaron Boodman (www.youngpup.net)
 * =================================================================================================
 * "Can I use this?"
 * 
 * Use of this library is governed by the Creative Commons Attribution 2.0 License. You can check it 
 * out at: http://creativecommons.org/licenses/by/2.0/
 *
 * Basically: You may copy, distribute, and eat this code as you wish. But you must give me credit 
 * for writing it. You may not misrepresent yourself as the author of this code.
 * =================================================================================================
 * "It's kinda hard to read, though"
 *
 * The uncompressed, commented version of this script can be found at: 
 * http://youngpup.net/projects/transMenus
 * =================================================================================================
 * updates:
 * 04.19.04 fixed cascade problem with menus nested greater than two levels.
 * 12.23.03 added hideCurrent for menu actuators with no menus. renamed to TransMenu.
 * 04.18.03	fixed render bug in IE 5.0 Mac by removing that browser from compatibility table ;)
 *			also made gecko check a little more strict by specifying build no.
 * ============================================================================================== */



//==================================================================================================
// Configuration properties
//==================================================================================================
//==================================================================================================
TransMenu.spacerGif = "img/x.gif";                     // path to a transparent spacer gif
TransMenu.dingbatOn = "img/arrowchild-on.gif";         // path to the active sub menu dingbat
TransMenu.dingbatOff = "img/arrowchild-off.gif";       // path to the inactive sub menu dingbat
TransMenu.dingbatSize = 8;                             // size of the dingbat (square shape assumed)
TransMenu.menuPadding = 0;                             // padding between menu border and items grid
TransMenu.itemPadding = 5;                             // additional padding around each item
TransMenu.leftPadding = 20;                            // additional padding from left of each item
TransMenu.shadowSize = 2;                              // size of shadow under menu
TransMenu.shadowOffset = 3;                            // distance shadow should be offset from leading edge
TransMenu.shadowColor = "#333333";                     // color of shadow (transparency is set in CSS)
TransMenu.shadowPng = "img/grey-40.png";               // a PNG graphic to serve as the shadow for mac IE5
TransMenu.backgroundColor = "#e6f2f7";                 // color of the background (transparency set in CSS)
TransMenu.backgroundPng = "img/white-90.png";          // a PNG graphic to server as the background for mac IE5
TransMenu.hideDelay = 1000;                            // number of milliseconds to wait before hiding a menu
TransMenu.slideTime = 200;                             // number of milliseconds it takes to open and close a menu
TransMenu.subpad_x = 0;								   // Horizontal Padding between top right corner of item menu and its submenu (level > 2)
TransMenu.subpad_y = -2;							   // Vertical Padding between top right corner of item menu and its submenu (level > 2)
TransMenu.fixedWidth = true;						   // Set Width of menu is auto fixed (with text string) Width or not
TransMenu.menuWidth = 140;							   // The Width of menu if fixedWidth = true.

//==================================================================================================
// Internal use properties
//==================================================================================================
TransMenu.reference = {topLeft:1,topRight:2,bottomLeft:3,bottomRight:4};
TransMenu.direction = {down:1,right:2};
TransMenu.registry = [];
TransMenu._maxZ = 100;

TransMenu.updateImgPath = function (imgPath)
{
	TransMenu.spacerGif = imgPath + TransMenu.spacerGif;
	TransMenu.dingbatOn = imgPath + TransMenu.dingbatOn;
	TransMenu.dingbatOff = imgPath + TransMenu.dingbatOff;
	TransMenu.shadowPng = imgPath + TransMenu.shadowPng;
	TransMenu.backgroundPng = imgPath + TransMenu.backgroundPng;
}

//==================================================================================================
// Static methods
//==================================================================================================
// supporting win ie5+, mac ie5.1+ and gecko >= mozilla 1.0
TransMenu.isSupported = function() 
{
	var ua = navigator.userAgent.toLowerCase();
	var pf = navigator.platform.toLowerCase();
	var an = navigator.appName;
	var r = false;

	if (ua.indexOf("gecko") > -1 && navigator.productSub >= 20020605) r = true; // gecko >= moz 1.0
	else if (an == "Microsoft Internet Explorer") 
	{
		if (document.getElementById) 	// ie5.1+ mac,win
		{ 
			if (pf.indexOf("mac") == 0) 
			{
				r = /msie (\d(.\d*)?)/.test(ua) && Number(RegExp.$1) >= 5.1;
			}
			else r = true;
		}
	}

	return r;
}

// call this in onload once menus have been created
TransMenu.initialize = function() 
{
	for (var i = 0, menu = null; menu = this.registry[i]; i++) 
	{
		menu.initialize();
	}
}

// call this in document body to write out menu html
TransMenu.renderAll = function() 
{
	var aMenuHtml = [];
	for (var i = 0, menu = null; menu = this.registry[i]; i++) 
	{
		aMenuHtml[i] = menu.toString();
	}
	document.write(aMenuHtml.join(""));
}

//==================================================================================================
// TransMenu constructor (only called internally)
//==================================================================================================
// oActuator            : The thing that causes the menu to be shown when it is mousedover. Either a
//                        reference to an HTML element, or a TransMenuItem from an existing menu.
// iDirection           : The direction to slide out. One of TransMenu.direction.
// iLeft                : Left pixel offset of menu from actuator
// iTop                 : Top pixel offset of menu from actuator
// iReferencePoint      : Corner of actuator to measure from. One of TransMenu.referencePoint.
// parentMenuSet        : Menuset this menu will be added to.
//==================================================================================================
function TransMenu(oActuator, iDirection, iLeft, iTop, iReferencePoint, parentMenuSet) 
{
	// public methods
	this.addItem = addItem;
	this.addMenu = addMenu;
	this.toString = toString;
	this.initialize = initialize;
	this.isOpen = false;
	this.show = show;
	this.hide = hide;
	this.items = [];

	// events
	this.onactivate = new Function();       // when the menu starts to slide open
	this.ondeactivate = new Function();     // when the menu finishes sliding closed
	this.onmouseover = new Function();      // when the menu has been moused over
	this.onqueue = new Function();          // hack .. when the menu sets a timer to be closed a little while in the future
	this.ondequeue = new Function();

	// initialization
	this.index = TransMenu.registry.length;
	TransMenu.registry[this.index] = this;

	var id = "TransMenu" + this.index;
	var contentHeight = null;
	var contentWidth = null;
	var childMenuSet = null;
	var animating = false;
	var childMenus = [];
	var slideAccel = -1;
	var elmCache = null;
	var ready = false;
	var _this = this;
	var a = null;

	var pos = iDirection == TransMenu.direction.down ? "top" : "left";
	var dim = null;

	// private and public method implimentations
	function addItem(sText, sUrl, browserNav, active) 
	{
		var item = new TransMenuItem(sText, sUrl, this, browserNav, active);
		item._index = this.items.length;
		this.items[item._index] = item;
	}

	function addMenu(oMenuItem) 
	{
		if (!oMenuItem.parentMenu == this) 
			throw new Error("Cannot add a menu here");

		if (childMenuSet == null) 
			childMenuSet = new TransMenuSet(TransMenu.direction.right, TransMenu.subpad_x, TransMenu.subpad_y, TransMenu.reference.topRight);

		var m = childMenuSet.addMenu(oMenuItem);

		childMenus[oMenuItem._index] = m;
		m.onmouseover = child_mouseover;
		m.ondeactivate = child_deactivate;
		m.onqueue = child_queue;
		m.ondequeue = child_dequeue;

		return m;
	}

	function initialize() 
	{
		initCache();
		initEvents();
		initSize();
		ready = true;
	}

	function show() 
	{
		//dbg_dump("show");
		if (ready) 
		{
			_this.isOpen = true;
			animating = true;
			setContainerPos();
			elmCache["clip"].style.visibility = "visible";
			elmCache["clip"].style.zIndex = TransMenu._maxZ++;
			//dbg_dump("maxZ: " + TransMenu._maxZ);
			slideStart();
			_this.onactivate();
		}
	}

	function hide() 
	{
		if (ready) 
		{
			_this.isOpen = false;
			animating = true;

			for (var i = 0, item = null; item = elmCache.item[i]; i++) 
					dehighlight(item);

			if (childMenuSet) childMenuSet.hide();

			slideStart();
			_this.ondeactivate();
			
			if (!oActuator.parentMenu) 
			{
				oActuator.className = oActuator.className.replace(/ jahover-active/, '');
				oActuator.className = oActuator.className.replace(/ jahover/, '');
			}
		}
	}

	function setContainerPos() 
	{
		var sub = oActuator.constructor == TransMenuItem; 
		var act = sub ? oActuator.parentMenu.elmCache["item"][oActuator._index] : oActuator; 
		var el = act;
		
		var x = 0;
		var y = 0;

		
		var minX = 0;
		var maxX = (window.innerWidth ? window.innerWidth : document.body.clientWidth) - parseInt(elmCache["clip"].style.width);
		var minY = 0;
		var maxY = (window.innerHeight ? window.innerHeight : document.body.clientHeight) - parseInt(elmCache["clip"].style.height);
		maxX = 10000;
		maxY = 10000;

		// add up all offsets... subtract any scroll offset
		while (sub ? el.parentNode.className.indexOf("transMenu") == -1 : el.offsetParent) 
		{
			x += el.offsetLeft;
			y += el.offsetTop;

			if (el.scrollLeft) x -= el.scrollLeft;
			if (el.scrollTop) y -= el.scrollTop;
			
			el = el.offsetParent;
		}

		if (oActuator.constructor == TransMenuItem) 
		{
			x += parseInt(el.parentNode.style.left);
			y += parseInt(el.parentNode.style.top);
		}

		switch (iReferencePoint) 
		{
			case TransMenu.reference.topLeft:
				break;
			case TransMenu.reference.topRight:
				x += act.offsetWidth;
				break;
			case TransMenu.reference.bottomLeft:
				y += act.offsetHeight;
				break;
			case TransMenu.reference.bottomRight:
				x += act.offsetWidth;
				y += act.offsetHeight;
				break;
		}

		x += iLeft;
		y += iTop;

		x = Math.max(Math.min(x, maxX), minX);
		y = Math.max(Math.min(y, maxY), minY);

		elmCache["clip"].style.left = x + "px";
		elmCache["clip"].style.top = y + "px";
	}

	function slideStart() 
	{
		var x0 = parseInt(elmCache["content"].style[pos]);
		var x1 = _this.isOpen ? 0 : -dim;

		if (a != null) a.stop();
		a = new Accelimation(x0, x1, TransMenu.slideTime, slideAccel);

		a.onframe = slideFrame;
		a.onend = slideEnd;

		a.start();
	}

	function slideFrame(x) 
	{
		elmCache["content"].style[pos] = x + "px";
	}

	function slideEnd() 
	{
		if (!_this.isOpen) 
			elmCache["clip"].style.visibility = "hidden";
		animating = false;
	}

	function initSize() 
	{
		// everything is based off the size of the items table...
		var ow = elmCache["items"].offsetWidth;
		var oh = elmCache["items"].offsetHeight;
		var ua = navigator.userAgent.toLowerCase();

		// clipping container should be ow/oh + the size of the shadow
		elmCache["clip"].style.width = ow + TransMenu.shadowSize +  2 + "px";
		elmCache["clip"].style.height = oh + TransMenu.shadowSize + 2 + "px";

		// same with content...
		elmCache["content"].style.width = ow + TransMenu.shadowSize + "px";
		elmCache["content"].style.height = oh + TransMenu.shadowSize + "px";

		contentHeight = oh + TransMenu.shadowSize;
		contentWidth = ow + TransMenu.shadowSize;
		
		dim = iDirection == TransMenu.direction.down ? contentHeight : contentWidth;

		// set initially closed
		elmCache["content"].style[pos] = -dim - TransMenu.shadowSize + "px";
		elmCache["clip"].style.visibility = "hidden";

		// if *not* mac/ie 5
		if (ua.indexOf("mac") == -1 || ua.indexOf("gecko") > -1) 
		{
			// set background div to offset size
			elmCache["background"].style.width = ow + "px";
			elmCache["background"].style.height = oh + "px";
			elmCache["background"].style.backgroundColor = TransMenu.backgroundColor;

			// shadow left starts at offset left and is offsetHeight pixels high
			elmCache["shadowRight"].style.left = ow + "px";
			elmCache["shadowRight"].style.height = oh - (TransMenu.shadowOffset - TransMenu.shadowSize) + "px";
			elmCache["shadowRight"].style.backgroundColor = TransMenu.shadowColor;

			// shadow bottom starts at offset height and is offsetWidth - shadowOffset 
			// pixels wide (we don't want the bottom and right shadows to overlap or we 
			// get an extra bright bottom-right corner)
			elmCache["shadowBottom"].style.top = oh + "px";
			elmCache["shadowBottom"].style.width = ow - TransMenu.shadowOffset + "px";
			elmCache["shadowBottom"].style.backgroundColor = TransMenu.shadowColor;
		}
		// mac ie is a little different because we use a PNG for the transparency
		else 
		{
			// set background div to offset size
			elmCache["background"].firstChild.src = TransMenu.backgroundPng;
			elmCache["background"].firstChild.width = ow;
			elmCache["background"].firstChild.height = oh;

			// shadow left starts at offset left and is offsetHeight pixels high
			elmCache["shadowRight"].firstChild.src = TransMenu.shadowPng;
			elmCache["shadowRight"].style.left = ow + "px";
			elmCache["shadowRight"].firstChild.width = TransMenu.shadowSize;
			elmCache["shadowRight"].firstChild.height = oh - (TransMenu.shadowOffset - TransMenu.shadowSize);

			// shadow bottom starts at offset height and is offsetWidth - shadowOffset 
			// pixels wide (we don't want the bottom and right shadows to overlap or we 
			// get an extra bright bottom-right corner)
			elmCache["shadowBottom"].firstChild.src = TransMenu.shadowPng;
			elmCache["shadowBottom"].style.top = oh + "px";
			elmCache["shadowBottom"].firstChild.height = TransMenu.shadowSize;
			elmCache["shadowBottom"].firstChild.width = ow - TransMenu.shadowOffset;
		}
	}
        
	function initCache() 
	{
		var menu = document.getElementById(id);
		var all = menu.all ? menu.all : menu.getElementsByTagName("*"); // IE/win doesn't support * syntax, but does have the document.all thing

		elmCache = {};
		elmCache["clip"] = menu;
		elmCache["item"] = [];
		
		for (var i = 0, elm = null; elm = all[i]; i++) 
		{
			switch (elm.className) 
			{
				case "items":
				case "content":
				case "background":
				case "shadowRight":
				case "shadowBottom":
					elmCache[elm.className] = elm;
					break;
				case "item":
					elm._index = elmCache["item"].length;
					elmCache["item"][elm._index] = elm;
					break;
			}
		}

		// hack!
		_this.elmCache = elmCache;
	}

	function initEvents() 
	{
		// hook item mouseover
		for (var i = 0, item = null; item = elmCache.item[i]; i++) 
		{
			item.onmouseover = item_mouseover;
			item.onmouseout = item_mouseout;
			item.onclick = item_click;
		}

		// hook actuation
		if (typeof oActuator.tagName != "undefined") 
		{
			oActuator.onmouseover = actuator_mouseover;
			oActuator.onmouseout = actuator_mouseout;
		}

		// hook menu mouseover
		elmCache["content"].onmouseover = content_mouseover;
		elmCache["content"].onmouseout = content_mouseout;
	}

	function highlight(oRow) 
	{
		oRow.className = "item hover";
		if (childMenus[oRow._index]) 
			oRow.lastChild.firstChild.src = TransMenu.dingbatOn;
	}

	function dehighlight(oRow) 
	{
		oRow.className = "item";
		if (childMenus[oRow._index]) 
			oRow.lastChild.firstChild.src = TransMenu.dingbatOff;
	}

	function item_mouseover() 
	{
		if (!animating) 
		{
			highlight(this);

			if (childMenus[this._index]) 
				childMenuSet.showMenu(childMenus[this._index]);
			else if (childMenuSet) 
				childMenuSet.hide();
		}
	}

	function item_mouseout() 
	{
		if (!animating) 
		{
			if (childMenus[this._index])
				childMenuSet.hideMenu(childMenus[this._index]);
			else    // otherwise child_deactivate will do this
				dehighlight(this);
		}
	}

	function item_click() 
	{
		if (!animating) 
		{
			if (_this.items[this._index].url) 
			{
				switch (_this.items[this._index].browserNav) 
				{
					// cases are slightly different
					case 1:			// open in a new window
						window.open(_this.items[this._index].url, '', '');;
						break;
					case 2:			// open in a popup window
						window.open(_this.items[this._index].url, '', 'toolbar=no,location=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=780,height=550');;
						break;
					case 3:			// don't link it
						break;
					default:		// formerly case 2
						// open in parent window
						location.href = _this.items[this._index].url;
					break;
				}
			}
		}
	}

	function actuator_mouseover() 
	{
		parentMenuSet.showMenu(_this);
		if (!oActuator.parentMenu) 
		{
			if (oActuator.className.indexOf(' jahover') < 0)
			{
				if (oActuator.className.indexOf('-active') < 0)
					oActuator.className += ' jahover';
				else
					oActuator.className += ' jahover-active';              			
			}
		}
	}

	function actuator_mouseout() 
	{
		parentMenuSet.hideMenu(_this);
	}

	function content_mouseover() 
	{
		if (!animating) 
		{
			parentMenuSet.showMenu(_this);
			_this.onmouseover();
		}
	}

	function content_mouseout() 
	{
		if (!animating) 
		{
			parentMenuSet.hideMenu(_this);
		}
	}

	function child_mouseover() 
	{
		if (!animating) 
		{
			parentMenuSet.showMenu(_this);
		}
	}

	function child_deactivate() 
	{
		for (var i = 0; i < childMenus.length; i++) 
		{
			if (childMenus[i] == this) 
			{
				dehighlight(elmCache["item"][i]);
				break;
			}
		}
	}

	function child_queue() 
	{
		parentMenuSet.hideMenu(_this);
	}

	function child_dequeue() 
	{
		parentMenuSet.showMenu(_this);
	}

	function toString() 
	{
		var aHtml = [];
		var sClassName = "transMenu" + (oActuator.constructor != TransMenuItem ? " top" : "");

		for (var i = 0, item = null; item = this.items[i]; i++) 
		{
			aHtml[i] = item.toString(childMenus[i]);
		}

		return '<div id="' + id + '" class="' + sClassName + '">' + 
				'<div class="content"><table class="items" cellpadding="0" cellspacing="0" border="0">' + 
				'<tr><td colspan="2"><img src="' + TransMenu.spacerGif + '" width="1" height="' + TransMenu.menuPadding + '"></td></tr>' + 
				aHtml.join('') + 
				'<tr><td colspan="2"><img src="' + TransMenu.spacerGif + '" width="1" height="' + TransMenu.menuPadding + '"></td></tr></table>' + 
				'<div class="shadowBottom"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
				'<div class="shadowRight"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
				'<div class="background"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
				'</div></div>';
	}
}


//==================================================================================================
// TransMenuSet
//==================================================================================================
// iDirection           : The direction to slide out. One of TransMenu.direction.
// iLeft                : Left pixel offset of menus from actuator
// iTop                 : Top pixel offset of menus from actuator
// iReferencePoint      : Corner of actuator to measure from. One of TransMenu.referencePoint.
//==================================================================================================
TransMenuSet.registry = [];

function TransMenuSet(iDirection, iLeft, iTop, iReferencePoint) 
{
	// public methods
	this.addMenu = addMenu;
	this.showMenu = showMenu;
	this.hideMenu = hideMenu;
	this.hide = hide;
	this.hideCurrent = hideCurrent;

	// initialization
	var menus = [];
	var _this = this;
	var current = null;

	this.index = TransMenuSet.registry.length;
	TransMenuSet.registry[this.index] = this;

	// method implimentations...
	function addMenu(oActuator) 
	{
		var m = new TransMenu(oActuator, iDirection, iLeft, iTop, iReferencePoint, this);
		menus[menus.length] = m;
		return m;
	}

	function showMenu(oMenu) 
	{
		if (oMenu != current) 
		{
			// close currently open menu
			if (current != null) hide(current);        

			// set current menu to this one
			current = oMenu;

			// if this menu is closed, open it
			oMenu.show();
		}
		else 
		{
			// hide pending calls to close this menu
			cancelHide(oMenu);
		}
	}

	function hideMenu(oMenu) 
	{
		//dbg_dump("hideMenu a " + oMenu.index);
		if (current == oMenu && oMenu.isOpen) 
		{
			//dbg_dump("hideMenu b " + oMenu.index);
			if (!oMenu.hideTimer) scheduleHide(oMenu);
		}
	}

	function scheduleHide(oMenu) 
	{
		//dbg_dump("scheduleHide " + oMenu.index);
		oMenu.onqueue();
		oMenu.hideTimer = window.setTimeout("TransMenuSet.registry[" + _this.index + "].hide(TransMenu.registry[" + oMenu.index + "])", TransMenu.hideDelay);
	}

	function cancelHide(oMenu) 
	{
		//dbg_dump("cancelHide " + oMenu.index);
		if (oMenu.hideTimer) 
		{
			oMenu.ondequeue();
			window.clearTimeout(oMenu.hideTimer);
			oMenu.hideTimer = null;
		}
	}

	function hide(oMenu) 
	{   
		if (!oMenu && current) oMenu = current;
		if (oMenu && current == oMenu && oMenu.isOpen) 
		{
			hideCurrent();
		}
	}

	function hideCurrent() 
	{
		if (null != current) 
		{
			cancelHide(current);
			current.hideTimer = null;
			current.hide();
			current = null;
		}
	}
}

//==================================================================================================
// TransMenuItem (internal)
// represents an item in a dropdown
//==================================================================================================
// sText        : The item display text
// sUrl         : URL to load when the item is clicked
// oParent      : Menu this item is a part of
//==================================================================================================
function TransMenuItem(sText, sUrl, oParent, browserNav, active) 
{
	this.toString = toString;
	this.text = sText;
	this.url = sUrl;
	this.browserNav = browserNav;
	this.parentMenu = oParent;
	this.active = active;

	function toString(bDingbat) 
	{
		var sDingbat = bDingbat ? TransMenu.dingbatOff : TransMenu.spacerGif;
		var iEdgePaddingLeft = TransMenu.itemPadding + TransMenu.menuPadding + TransMenu.leftPadding;
		var iEdgePaddingRight = TransMenu.itemPadding + TransMenu.menuPadding;
		var sPaddingLeft = "padding:" + TransMenu.itemPadding + "px; padding-left:" + iEdgePaddingLeft + "px;"
		var sPaddingRight = "padding:" + TransMenu.itemPadding + "px; padding-right:" + iEdgePaddingRight + "px;"
		var id = active?' id="active" ':'';
		if (TransMenu.fixedWidth == false)
		{
			/*return '<tr class="item"'+id+'><td nowrap style="' + sPaddingLeft + sPaddingRight + '"><div style="background: url(' + sDingbat + ') right no-repeat;">' + 
				sText + '</div></td></tr>';*/
			return '<tr class="item"'+id+'><td nowrap style="' + sPaddingLeft + '">' + 
					sText + '</td><td width="10" style="' + sPaddingRight + '">' + 
					'<img src="' + sDingbat + '" width="8" height="8"></td></tr>';
		}
		else
		{
			return '<tr class="item"'+id+'><td nowarp width="' + TransMenu.menuWidth + '" style="' + sPaddingLeft + ';float:left;">' + 
					sText + '</td><td width="0" style=";">' + 
					'<img src="' + sDingbat + '" width="8" height="8" style="float:left" /></td></tr>';	
		}
	}
}

//=====================================================================
// Accel[erated] [an]imation object
// change a property of an object over time in an accelerated fashion
//=====================================================================
// obj  : reference to the object whose property you'd like to animate
// prop : property you would like to change eg: "left"
// to   : final value of prop
// time : time the animation should take to run
// zip	: optional. specify the zippiness of the acceleration. pick a 
//		  number between -1 and 1 where -1 is full decelerated, 1 is 
//		  full accelerated, and 0 is linear (no acceleration). default
//		  is 0.
// unit	: optional. specify the units for use with prop. default is 
//		  "px".
//=====================================================================
// bezier functions lifted from the lib_animation.js file in the 
// 13th Parallel API. www.13thparallel.org
//=====================================================================
function Accelimation(from, to, time, zip) 
{
	if (typeof zip  == "undefined") zip  = 0;
	if (typeof unit == "undefined") unit = "px";

	this.x0     = from;
	this.x1		= to;
	this.dt		= time;
	this.zip	= -zip;
	this.unit	= unit;
	this.timer	= null;
	this.onend	= new Function();
    this.onframe= new Function();
}

//=====================================================================
// public methods
//=====================================================================

// after you create an accelimation, you call this to start it-a runnin'
Accelimation.prototype.start = function() 
{
	this.t0 = new Date().getTime();
	this.t1 = this.t0 + this.dt;
	var dx	= this.x1 - this.x0;
	this.c1 = this.x0 + ((1 + this.zip) * dx / 3);
	this.c2 = this.x0 + ((2 + this.zip) * dx / 3);
	Accelimation._add(this);
}

// and if you need to stop it early for some reason...
Accelimation.prototype.stop = function() 
{
	Accelimation._remove(this);
}

//=====================================================================
// private methods
//=====================================================================

// paints one frame. gets called by Accelimation._paintAll.
Accelimation.prototype._paint = function(time) 
{
	if (time < this.t1) 
	{
		var elapsed = time - this.t0;
	    this.onframe(Accelimation._getBezier(elapsed/this.dt,this.x0,this.x1,this.c1,this.c2));
    }
	else this._end();
}

// ends the animation
Accelimation.prototype._end = function() 
{
	Accelimation._remove(this);
    this.onframe(this.x1);
	this.onend();
}

//=====================================================================
// static methods (all private)
//=====================================================================

// add a function to the list of ones to call periodically
Accelimation._add = function(o) 
{
	var index = this.instances.length;
	this.instances[index] = o;
	// if this is the first one, start the engine
	if (this.instances.length == 1) 
	{
		this.timerID = window.setInterval("Accelimation._paintAll()", this.targetRes);
	}
}

// remove a function from the list
Accelimation._remove = function(o) 
{
	for (var i = 0; i < this.instances.length; i++) 
	{
		if (o == this.instances[i]) 
		{
			this.instances = this.instances.slice(0,i).concat( this.instances.slice(i+1) );
			break;
		}
	}
	// if that was the last one, stop the engine
	if (this.instances.length == 0) 
	{
		window.clearInterval(this.timerID);
		this.timerID = null;
	}
}

// "engine" - call each function in the list every so often
Accelimation._paintAll = function() 
{
	var now = new Date().getTime();
	for (var i = 0; i < this.instances.length; i++) 
	{
		this.instances[i]._paint(now);
	}
}


// Bezier functions:
Accelimation._B1 = function(t) { return t*t*t }
Accelimation._B2 = function(t) { return 3*t*t*(1-t) }
Accelimation._B3 = function(t) { return 3*t*(1-t)*(1-t) }
Accelimation._B4 = function(t) { return (1-t)*(1-t)*(1-t) }


//Finds the coordinates of a point at a certain stage through a bezier curve
Accelimation._getBezier = function(percent,startPos,endPos,control1,control2) 
{
	return endPos * this._B1(percent) + control2 * this._B2(percent) + control1 * this._B3(percent) + startPos * this._B4(percent);
}

//=====================================================================
// static properties
//=====================================================================

Accelimation.instances = [];
Accelimation.targetRes = 10;
Accelimation.timerID = null;

//=====================================================================
// IE win memory cleanup
//=====================================================================

if (window.attachEvent) 
{
	var cearElementProps = [
		'data',
		'onmouseover',
		'onmouseout',
		'onmousedown',
		'onmouseup',
		'ondblclick',
		'onclick',
		'onselectstart',
		'oncontextmenu'
	];

	window.attachEvent("onunload", function(){
        var el;
        for(var d = document.all.length;d--;){
            el = document.all[d];
            for(var c = cearElementProps.length;c--;){
                el[cearElementProps[c]] = null;
            }
        }
	});
}