// menu.js

var menus = [];

// --- menu class ---
function menu (item_struct, pos, styles) {
	// browser check
	this.item_struct = item_struct;
	this.pos = pos;
	this.styles = styles;
	this.id = menus.length;
	this.items = [];
	this.children = [];
	
	this.add_item = menu_add_item;
	this.hide = menu_hide;
	
	this.onclick = menu_onclick;
	this.onmouseout = menu_onmouseout;
	this.onmouseover = menu_onmouseover;
	this.onmousedown = menu_onmousedown;
	
	var i;
	for (i = 0; i < this.item_struct.length; i++)
		new menu_item(i, this, this);
	for (i = 0; i < this.children.length; i++)
		this.children[i].visibility(true);
	menus[this.id] = this;
}
function menu_add_item (item) {
	var id = this.items.length;
	this.items[id] = item;
	return (id);
}
function menu_hide () {
	for (var i = 0; i < this.items.length; i++) {
		this.items[i].visibility(false);
		this.items[i].switch_style('onmouseout');
	}
}
function menu_onclick (id) {
	var item = this.items[id];
	return (item.fields[1] ? true : false);
}
function menu_onmouseout (id) {
	this.hide_timer = setTimeout('menus['+ this.id +'].hide();',
		this.pos['hide_delay'][this.active_item.depth]);
	if (this.active_item.id == id)
		this.active_item = null;
}
function menu_onmouseover (id) {
	this.active_item = this.items[id];
	clearTimeout(this.hide_timer);
	var curr_item, visib;
	for (var i = 0; i < this.items.length; i++) {
		curr_item = this.items[i];
		visib = (curr_item.arrpath.slice(0, curr_item.depth).join('_') ==
			this.active_item.arrpath.slice(0, curr_item.depth).join('_'));
		if (visib)
			curr_item.switch_style (
				curr_item == this.active_item ? 'onmouseover' : 'onmouseout');
		curr_item.visibility(visib);
	}
}
function menu_onmousedown (id) {
	this.items[id].switch_style('onmousedown');
}
// --- menu item Class ---
function menu_item (path, parent, container) {
	this.path = new String (path);
	this.parent = parent;
	this.container = container;
	this.arrpath = this.path.split('_');
	this.depth = this.arrpath.length - 1;
	// get pointer to item's data in the structure
	var struct_path = '', i;
	for (i = 0; i <= this.depth; i++)
		struct_path += '[' + (Number(this.arrpath[i]) + (i ? 2 : 0)) + ']';
	eval('this.fields = this.container.item_struct' + struct_path);
	if (!this.fields) return;
	
	// assign methods	
	this.get_x = mitem_get_x;
	this.get_y = mitem_get_y;
	// these methods may be different for different browsers (i.e. non DOM compatible)
	this.init = mitem_init;
	this.visibility = mitem_visibility;
	this.switch_style = mitem_switch_style;
	
	// register in the collections
	this.id = this.container.add_item(this);
	parent.children[parent.children.length] = this;
	
	// init recursively
	this.init();
	this.children = [];
	var child_count = this.fields.length - 2;
	for (i = 0; i < child_count; i++)
		new menu_item (this.path + '_' + i, this, this.container);
	this.switch_style('onmouseout');
}
function mitem_init() {
	document.write (
		'<a id="mi_' + this.container.id + '_'
			+ this.id +'" class="m' + this.container.id + 'l' + this.depth 
			+'o" href="' + this.fields[1] + '" style="position: absolute; top: '
			+ this.get_y() + 'px; left: '	+ this.get_x() + 'px; width: '
			+ this.container.pos['width'][this.depth] + 'px; height: '
			+ this.container.pos['height'][this.depth] + 'px; visibility: hidden;'
			+' background: black; color: white; z-index: ' + (this.depth+10000) + ';" '
			+ 'onclick="return menus[' + this.container.id + '].onclick('
			+ this.id + ');" onmouseout="menus[' + this.container.id + '].onmouseout('
			+ this.id + ');" onmouseover="menus[' + this.container.id + '].onmouseover('
			+ this.id + ');" onmousedown="menus[' + this.container.id + '].onmousedown('
			+ this.id + ');"><div class="m'  + this.container.id + 'l' + this.depth + 'i">'
			+ this.fields[0] + "</div></a>\n"
		);
	this.element = document.getElementById('mi_' + this.container.id + '_' + this.id);
}
function mitem_visibility(make_visible) {
	if (make_visible != null) {
		if (this.visible == make_visible) return;
		this.visible = make_visible;
		if (make_visible)
			this.element.style.visibility = 'visible';
		else if (this.depth)
			this.element.style.visibility = 'hidden';
	}
	return (this.visible);
}
function mitem_get_x() {
	var value = 0;
	for (var i = 0; i <= this.depth; i++)
		value += this.container.pos['block_left'][i]
		+ this.arrpath[i] * this.container.pos['left'][i];
	return (value);
}
function mitem_get_y() {
	var value = 0;
	for (var i = 0; i <= this.depth; i++)
		value += this.container.pos['block_top'][i]
		+ this.arrpath[i] * this.container.pos['top'][i];
	return (value);
}
function mitem_switch_style(state) {
	if (this.state == state) return;
	this.state = state;
	var style = this.container.styles[state];
	for (var i = 0; i < style.length; i += 2)
		if (style[i] && style[i+1])
			eval('this.element.style.' + style[i] + "='" 
			+ style[i+1][this.depth] + "';");
}

// menu_items.js file

var MENU_ITEMS =[

	["Terms of Use", "/Terms.shtml",
		["Please read this", "/Terms.shtml"]
	],
	["Awards", "/awards.shtml",
		["We've been recognized", "/awards.shtml"]
	],

	[" ", null],
	["Interactive Activities", "/Curriculum/index.shtml",
		["Memory and Matching", "/Curriculum/index.shtml"],
		["Arithmetic", "/Curriculum/index.shtml#arithmetic"],
		["Algebra", "/Curriculum/index.shtml#algebra"],
		["Logic", "/Curriculum/index.shtml#logic"],
		["Geometry", "/Curriculum/index.shtml#geometry"],
		["Fractals", "/Curriculum/index.shtml#f"],
		["Outline Mathematics", "/Outline/index.shtml"],
		["Probability", "/Curriculum/index.shtml#probability"],
		["Visual Illusions", "/Curriculum/index.shtml#illusions"],
		["Calculus", "/Curriculum/index.shtml#calculus"],
		["Fallacies", "/Curriculum/index.shtml#Fallacies"],
		["Math Magic", "/Curriculum/index.shtml#mathmagic"],
		["Combinatorics", "/Curriculum/index.shtml#combinatorics"],
		["Mathematical Droodles", "/Curriculum/index.shtml#droodles"],
		["Puzzles & Games", "/Curriculum/index.shtml#puzzles"],
		["Combinatorial Games", "/Curriculum/index.shtml#games"],
		["Social Science", "/Curriculum/index.shtml#social"],
		["Miscellaneous Demos", "/Curriculum/index.shtml#demonstrations"]
	],

	["The CTK Exchange", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctkforum.cgi",
		["Ask questions, post answers", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi"],
		["Early Math", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID1&conf=DCConfID1"],
		["Middle School", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID2&conf=DCConfID1"],
		["High School", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID3&conf=DCConfID1"],
		["College Math", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID6&conf=DCConfID1"],
		["This and That", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID4&conf=DCConfID1"],
		["Guest book", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID5&conf=DCConfID1"]
	],

	[" ", null],

	["Games & Puzzles", "/games.shtml",
		["Three Jugs Problem", "/ctk/Water.shtml"],
		["Box Labels", "/SimpleGames/PickLabel.shtml"],
		["Fish Soup game", "/SimpleGames/SoupFish.shtml"],
		["Josephus Flavius' problem", "/recurrence/flavius.shtml"],
		["Peg Solitaire", "/proofs/pegsolitaire.shtml"],
		["Scoring", "/recurrence/Scoring.shtml"],
		["Toads And Frogs Puzzle", "/SimpleGames/FrogsAndToads.shtml"],
		["Tower of Hanoi", "/recurrence/hanoi.shtml"],
		["Tromino Puzzle", "/Curriculum/Games/TrominoPuzzle.shtml"],
		["And much much more ...", "/games.shtml"]
	],
	["Arithmetic/Algebra", "/algebra.shtml",
		["Base Conversion", "/recurrence/conversion.shtml"],
		["Divisibility Criteria", "/blue/divisibility.shtml"],
		["Euclid's Game", "/blue/EuclidAlg.shtml"],
		["Fast Arithmetic Tips", "/arithmetic/rapid/index.shtml"],
		["Hour glass timing", "/water2.shtml#HourGlass"],
		["Lewis Carroll's Logic Game", "/LewisCarroll/LCGame.shtml"],
		["Magic in Square", "/Curriculum/Magic/MagicInSquare.shtml"],
		["Napier Bones", "/blue/Napier.shtml"],
		["Number Guessing Game", "/blue/Cards.shtml"],
		["Venn Diagrams", "/LewisCarroll/VennDiagrams.shtml"],
		["And much much more ...", "/algebra.shtml"]
	],
	["Geometry", "/geometry.shtml",
		["3 Utilities Puzzle", "/do_you_know/3Utilities.shtml"],
		["Altitudes", "/triangle/altitudes.shtml"],
		["Angle Bisectors", "/triangle/ABisector.shtml"],
		["Area of Parallelogram", "/Curriculum/Geometry/AreaOfParallelogram.shtml"],
		["Asymmetric Propeller", "/Curriculum/Geometry/AsymmetricPropeller.shtml"],
		["Butterfly Theorem", "/pythagoras/Butterfly.shtml"],
		["Color Cycling on Mandelbrot", "/Curriculum/Magic/MandelCycle.shtml"],
		["Emergence of Chaos", "/blue/chaos.shtml"],
		["Delian Problem Solved", "/Curriculum/Geometry/Delian.shtml"],
		["Eyeball Theorem", "/Curriculum/Geometry/Eyeball.shtml"],
		["Fagnano's problem", "/triangle/Fagnano.shtml"],
		["Inversion: Reflection in Circle", "/Curriculum/Geometry/SymmetryInCircle.shtml"],
		["Morley's Miracle", "/triangle/Morley/index.shtml"],
		["Poles and Polars", "/Curriculum/Geometry/PolePolar.shtml"],
		["Many Proofs of Pythagoras' Th", "/pythagoras/index.shtml"],
		["Triangle geometry", "/triangle/index.shtml"],
		["And much much more ...", "/geometry.shtml"]
	],
	["Fractals", "/Curriculum/index.shtml#f",
  ["All Peano Curves", "/Curriculum/Geometry/PeanoComplete.shtml"],
  ["Dot Patterns", "/Curriculum/Algebra/DotPatterns.shtml"],
  ["Emergence of Chaos", "/blue/chaos.shtml"],
  ["Iterated Function Systems", "/Curriculum/Geometry/ifs.shtml"],
  ["Indexing of Julia Sets", "/Curriculum/Algebra/JuliaIndexing.shtml"],
  ["Trema Removal", "/Curriculum/Geometry/StringFSM.shtml"],
  ["and more ...", "/Curriculum/index.shtml#f"],
 ],
	["Outline Mathematics", "/Outline/index.shtml",
  ["Word problems", "/Outline/index.shtml#WordProblems"],
  ["Logic problems", "/Outline/index.shtml#logic"],
  ["Arithmetic", "/Outline/index.shtml#Arithmetic"],
  ["Number Theory", "/Outline/index.shtml#NumberTheory"],
  ["Geometry", "/Outline/index.shtml#geometry"]
 ],
	["Probability", "/probability.shtml",
		["Birds On a Wire", "/Curriculum/Probability/BirdsOnWire.shtml"],
		["Buffon's Noodle", "/Curriculum/Probability/Buffon.shtml"],
		["Misuse of Statistics", "/do_you_know/misuse.shtml"],
		["Monty Hall Dilemma", "/hall.shtml"],
		["Parrondo's Paradox", "/ctk/Parrondo.shtml"],
		["Probability and Infinity", "/Probability/infinity.shtml"],
		["More ...", "/probability.shtml"]
	],
	["Eye Opener", "/pythagoras/tricky.shtml",
		["Breaking Chocolate Bars", "/proofs/chocolad.shtml"],
		["Curry's Paradox", "/Curriculum/Fallacies/CurryParadox.shtml#Curry"],
		["Farmer and Wife", "/SimpleGames/RFWH.shtml"],
		["Make Your Move, Kid!", "/pythagoras/MakeMove.shtml"],
		["Solitaire on the Circle", "/SimpleGames/CSolitaire.shtml"],
		["Two Butterflies Theorem", "/Curriculum/Geometry/TwoButterflies.shtml"],
		["And much more ...", "/pythagoras/tricky.shtml"]
	],
	["Analog Gadgets", "/pythagoras/ellipse.shtml",
		["Angle Trisection by Archimedes", "/pythagoras/archi.shtml"],
		["Abacus", "/Curriculum/Arithmetic/Abacus.shtml"],
		["Soroban", "/Curriculum/Arithmetic/Soroban.shtml"],
		["Geoboard", "/ctk/Pick.shtml"],
		["Peaucellier Linkage", "/pythagoras/invert.shtml"],
		["And more ...", "/pythagoras/ellipse.shtml"]
	],
	["Inventor's Paradox", "/Generalization/epairs.shtml",
		["Generalize!", "/Generalization/epairs.shtml"]
	],
	["Did you know?...", "/do_you_know/index.shtml",
		["Simple and unexpected facts", "/do_you_know/index.shtml"]
	],
	["Proofs", "/proofs/index.shtml",
		["Simple and elegant proofs", "/proofs/index.shtml"]
	],
	["Math as Language", "/language/index.shtml",
		["Hmm, try to do without...", "/language/index.shtml"]
	],
	["Things Impossible", "/impossible/index.shtml",
		["They are many ...", "/impossible/index.shtml"]
	],
	["My Logo", "/logo.shtml",
		["A one sided surface ...", "/logo.shtml"]
	],
	["Math Poll", "/math_intro.shtml",
		["What is Math. A poll.", "/math_intro.shtml"]
	],
	["Cut The Knot!", "/ctk/index.shtml",
		["On Math and Math Education", "/ctk/index.shtml"]
	],
	["MSET99 Talk", "/Mset99/index.shtml",
		["Once upon a time", "/Mset99/index.shtml"]
	],

	["Front page", "/front.shtml",
		["Ways to access the site", "/front.shtml"]
	],
	["Movie shortcuts", "/shortcut.shtml",
		["Creation of a Moebius strip", "/shortcut.shtml#MoebiusCreation"],
		["Formation of a 3-knot", "/shortcut.shtml#3knot"],
		["Creation of Klein's bottle", "/shortcut.shtml#Klein"],
		["Creation of a torus", "/shortcut.shtml#torus"],
		["More ...", "/shortcut.shtml"]
	],
	["Personal info", "/wanted.shtml",
		["Who've done it?", "/wanted.shtml"]
	],
	["Other Math Sites", "/collection.shtml",
		["Other good math sites", "/collection.shtml"]
	],
	["Guest book", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID5&conf=DCConfID1",
		["What do you think?", "http://www.cut-the-knot.org/cgi-bin/dcforum/ctk.cgi?az=list&forum=DCForumID5&conf=DCConfID1"]
	],
	["News Sites", "/sites.shtml",
		["News sites and a song", "/sites.shtml"]
	],
	["Reciprocal Links", "/ReciprocalMain.shtml",
		["We are linked to ...", "/ReciprocalMain.shtml"]
	]
	["Privacy Policy", "/Privacy.shtml",
		["Your privacy is paramount", "/Privacy.shtml"]
	],

	["Recommend this site", "/PHP/recommend.php",
		["Tell others about us.", "/recommend.shtml"]
	],
];

// menu_tpl.js
/* --- geometry and timing of the menu --- */
var MENU_POS = new Array();

	// item sizes for different levels of menu
	MENU_POS['height']     = [22, 22];
	MENU_POS['width']      = [110, 180];

	// menu block offset from the origin:
	//  for root level origin is upper left corner of the page
	//  for other levels origin is upper left corner of parent item
	MENU_POS['block_top']  = [140, 2];
	MENU_POS['block_left'] = [5, 100];

	// offsets between items of the same level
	MENU_POS['top']        = [21, 21];
	MENU_POS['left']       = [0, 0];

	// time in milliseconds before menu is hidden after cursor has gone out
	// of any items
	MENU_POS['hide_delay'] = [200, 200];

/* --- dynamic menu styles ---
note: you can add as many style properties as you wish but be not all browsers
are able to render them correctly. The only relatively safe properties are
'color' and 'background'.
*/

var MENU_STYLES = new Array();

	// default item state when it is visible but doesn't have mouse over
	MENU_STYLES['onmouseout'] = [
		'color', ['#000000', '#000000'],
		'background', ['#c0dcc5', '#C5DBCF'],
	];

	// state when item has mouse over it
	MENU_STYLES['onmouseover'] = [
		'color', ['#0000cc', '#0000cc'],
		'background', ['#C5DBCF', '#C5DBCF'],
	];

	// state when mouse button has been pressed on the item
	MENU_STYLES['onmousedown'] = [
		'color', ['#000000', '#000000'],
		'background', ['#cccccc', '#cccccc'],
	];