Ondřej Žára



JavaScript developer, living in Prague, Czech Republic. Currently employed by Seznam.cz.

Interested in my résumé? Try the GitHub version as well.


Name Description Technologies Source
Café Havoc My 7DRL 2016 (7-day roguelike contest) game. A rather traditional roguelike with an unorthodox story/setting. Coffeebreak length. rot.js GitHub
Warden's Duty My 7DRL 2015 (7-day roguelike contest) game. Lacks the traditional roguelike map and features over-sized ascii glyphs. You cannot really win this game, but you can try to get deeper than others. rot.js GitHub
Goldfish My 7DRL 2014 (7-day roguelike contest) game. Playable, winnable, losable. Features colorful and aesthetic maps, aquatic fauna and fishermen! rot.js GitHub
Custom Tetris My take on the GitHub Game Off 2013 contest. Modular Tetris game that offers configurable sides and multiplayer. Firebase GitHub
The Conception My 7DRL 2013 (7-day roguelike contest) game. Contains hexagons. And chlamydia. And much more. rot.js GitHub
The Royal Wedding Another coffebreak roguelike – with story, lighting, zombies and (sometimes) lutefisk! rot.js GitHub
Star Wars Miniature My take on the GitHub Game Off 2012 contest. rot.js GitHub
RailRL Small testbed game: hexes, trains, procedurally generated terrain. rot.js GitHub
Drago HTML5 remake of an old game by Blue Byte Software. Fully playable with cool graphics, animations, sounds and music! HAF GitHub
CSS Blockout 3D Tetris (Blockout) implemented using CSS 3D transforms. Submitted as a demo to Mozilla Dev Derby. Works correctly only in certain Browser/OS/HW combinations. CSS 3D GitHub
Rubik's cube Rubik's cube implemented using CSS 3D transforms. Submitted as a demo to Mozilla Dev Derby. Works correctly only in certain Browser/OS/HW combinations. CSS 3D
Clickmania JS port of a well-known time-killer. GitHub
Just Spaceships! Space shooter game: canvas, sounds effects, animated sprites, AI, websocket-based multiplayer! A presentation documenting the development process is available for online viewing. HAF, WebSockets, TeaJS GitHub
Atoms Traditional "atoms" game, well-known from Windows 3.1. Up to four players; local play with bots, multiplayer using Firebase. Firebase GitHub
Geometry Wars Multiplayer-only game, implemented using WebSockets. Score by drawing longest line; block enemies by placing circles. WebSockets, TeaJS GitHub
Brain Defense Zombies & lasers. What could go wrong? (Non-obsolete browser required.) HAF GitHub
Rogue Zombies Coffeebreak roguelike game. Warning: they will get you. Google Code GitHub
js-like JavaScript roguelike, heavily inspired by ADOM. Google Code GitHub


Name Description Technologies Source
mp Hybrid music player for desktop and the Web. Uses web APIs to play and visualize music. Web Audio API, 2d canvas, ArrayBuffers, ES 2015, Babel 6 GitHub
iv Image Viewer for nw.js and Electron. Unfinished due to poor image loading performance. GitHub
<instant-button> Instant Button Web Component. Colorful. Does sound FX! Web Components GitHub
<fix-me> & <to-do> Semi-serious Web Components Web Components GitHub
My Mind Online Mindmap editor, featuring variable layouts, (computed) values, storage to Firebase/GDrive and much more. Firebase GitHub
ie8eventtarget EventTarget polyfill for IE8, with complete capture support, MouseEvent and CustomEvent. GitHub
promise.js A tiny browser-based implementation of the "Promises/A+" spec. Passes all tests (using a tiny mocha2jasmine adapter). GitHub
JS Style Badge Create your own JS signature, based on your coding preferences. GitHub
rot.js ROguelike Toolkit, written in JavaScript. Cool dungeon-related stuff, interactive manual, documentation, tests! GitHub
HAF HTML5 Animation Framework is used to orchestrate complex canvas-based rendering projects, such as Brain Defense or Just Spaceships. It can be also used to perform several benchmarks and generally experiment with HTML canvas. Google Code GitHub
TeaJS Multi-purpose wrapper around V8 JS engine. Rich set of libraries included, including DB access, POSIX + Web Sockets, Apache module, … V8, C++ Google Code GitHub
Slides Yet another HTML/JS presentation system. Google Code GitHub
WWW SQL Designer Online tool for designing relational database schemas. Features schema saving, exporting to xml and sql script creation. GitHub
Gallery Personal photogallery.
Cookbook Written in PHP, uses MySQL database backend. Contains over 250 recipes. Google Code GitHub
oz.php Tiny PHP framework for rapid application development. Google Code GitHub
SZ Showcase A selection of photos taken in Sluneční zátoka.
Sluneční zátoka Photos from traditional children summer camp with long history and unique atmosphere. Years 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, and 2013.
Fire Commander Traditional two-pane file manager, implemented as Firefox extension / XUL application. Google Code GitHub
Syntax Tiny syntax highlighter. Google Code GitHub

Demos & Experiments

Name Description Technologies Source
elm-slides Simple slide deck written in Elm. Elm GitHub
Shooting the π Monte Carlo method for π approximation. Made for the 2016 pi day. 2d canvas
oscope.js JavaScript oscilloscope. Configurable, supports various input types, has XY mode. Web Audio API, 2d canvas GitHub
Rect-to-Polar converter Converts panoramic pictures into tiny planets 2d canvas GitHub
WebGL Fireworks WebGL + Web Audio API = awesome sound-driven fireworks! WebGL, Web Audio API GitHub
Photo Editor Basic photo adjustments using Web Workers. No server-side necessary. Load, adjust, crop, save, profit :-) Submitted as a demo to Mozilla DevDerby. Web Workers GitHub
Hash Bruteforcer Computes MD5 and SHA1 hashes using Web Workers. Submitted as a demo to Mozilla DevDerby. Web Workers GitHub
Pure CSS slides A non-JavaScript experiment: fully featured presentation system, using only HTML + CSS. No JS
Collaborative Draw WebSockets used to share drawing area. Support for lines, text and images. WebSockets, TeaJS GitHub
Harmoniums of Mercury Semi-interactive homage to Kurt Vonnegut. WebGL GitHub
Space-filling curves Recursive implementation of Peano/Hilbert curves, using canvas transformations.
a-g-e Adventure Game Engine, suitable for playing interactive gamebooks. Google Code GitHub
Coral generator Based on certain Game of Life rules; requires Web Workers. Web Workers GitHub
Worms Canvas-based worm simulation.
Canvas-based e-mail hash Visualizing e-mail addresses using various algorithms.
Canvas fireworks JavaScript fireworks using elementary mechanics, <canvas> and <audio> tags.
Compression benchmarks Trying to compress JSON with algorithms implemented in JS.
Canvas maze Produces a perfect maze and finds the path between two corners. In perfect maze, every two cells are connected with exactly one path.
Web Worker Fractals Interactive fractal drawer. Uses <canvas> and Web Workers (processing in multiple threads). Both Julia and Mandelbrot sets are supported. Submitted as a demo to Mozilla DevDerby. Web Workers GitHub
Derivation Captcha An accessibility experiment. PHP
HEX Creates SVG maps for "Expres" game (Dampfross, Railway Rivals).
Sun Interactive SVG Sun, logo for Sluneční zátoka.
Sudoku solver I wrote three Sudoku solvers. This one is fastest, featuring some optimizations in addition to brute force.


Presentation Year Language
ES 2015 – Co nového u JavaScriptu (GDG Jihlava) 2016 Czech
JavaScript a modularizace kódu (devel.cz 2016) 2016 Czech
JavaScript, vyvíjí se vůbec? (Posezení s vývojáři Seznam.cz) 2015 Czech
HTML5 a hry (čtvrtkon.cz) 2015 Czech
Výkonné částicové systémy a WebGL (devel.cz 2015) 2015 Czech
Panoramata na mapy.cz (VŠE Web Inkognito) 2014 Czech
HTTP/2 2014 Czech
Mapy API (FI MUNI) 2014 Czech
Jazyk PHP (ČVUT WA1) 2014 Czech
Skriptování na straně klienta (ČVUT WA1) 2014 Czech
JavaScriptové API mapy.cz (VŠE Web Inkognito) 2014 Czech
Roguelike development in JavaScript (IRDC 2014) 2014 English
Méně známé JS tipy a triky 2014 Czech
WebSocket: Provařené i méně známé partie (devel.cz 20132) 2013 Czech
HTML5 a Roguelike hry 2013 Czech
JS knihovny a další balast v roce 2013 2013 Czech
Mapy API známé i neznámé 2013 Czech
Lopaty, krumpáče a kladiva 2013 Czech
JIT Compilation 2013 Czech
JS Promises 2013 Czech
Cross-browser v roce 2013 (Barcamp Praha 2013) 2013 Czech
Předmět "Tvorba klientských aplikací v JavaScriptu" na FEL ČVUT 2013 Czech
Souřadnice, projekce a šikmé snímky 2013 Czech
HTML5 a CSS3 v praxi 2012 Czech
Distribuované verzovací systémy a Git 2012 Czech
Den s vývojáři – komplexní JS aplikace 2012 Czech
Just Spaceships! – development notes 2012 English, Czech
My job at Seznam.cz 2011 Czech
Mapy.cz API 2011 Czech
JavaScript & Seznam.cz 2010 Czech
Advanced JavaScript topics 2010 Czech
JavaScript introduction ? Czech
HTML5 for Web Designers 2011 Czech
HTML5 (compressed into one talk) 2012 Czech
HTML5 (set of four talks) 2011 Czech
AJAX 2011 Czech


Name Description
Petrov, Jeljena a já Another attempt to translate a song by Flight of the Conchords to my native language.
Firebase: krátké seznámení Introductory article about Firebase and its JS API
Moc kolíků na parketu An attempt to translate a song by Flight of the Conchords to my native language.
DOM události: co o nich možná nevíte Less-known properties and features of DOM events for advanced frontend developers.
JSConf.eu 2013 List of talks, slides, youtube links.
Začínáme s WebGL A series of a WebGL-related introductory articles.
JS MVC My critical opinions regarding JS MVC frameworks. Written in Czech language.
Rums Various rums I tasted, categorized and rated.
Comics Well-organized online comics I read.
Android games List of Android games I played (+ their rating).
Plain JS What can you do in plain JavaScript?
JSConf.eu 2012 List of talks, slides, youtube links.

Old stuff

Name Description
Canvas Audio Fireworks Regular fireworks mixed with HTML5 Audio API Extension.
oz.js Tiny but smart JS assistance for advanced coders.
Sluneční zátoka – přihlášky Website created to simplify the process of registering and administering attendees of Sluneční zátoka.
Dungeon-related algorithms Maze generation, FOV computation, turn scheduling.
Wild West Browser-based arena for simple but interesting fights of JavaScript AIs, based on a child's play.
Fallout 3 hack tool An attempt to simplify the Fallout 3 hacking process.
WWW SQL Designer 1.x Old version of a popular tool.
PHP Templates Original and lightweight (10kB), but powerful templating engine. Used in various websites. Current version: 2.3. Obsoleted by oz.php.
Showcase Some fine photos taken with my old and crappy Fujifilm FinePix S5000.
OAT Gallery Open source PHP/JS-based complete personal photogallery solution. Created with OpenLink Ajax Toolkit, with map and timeline.
OAT JavaScript/AJAX toolkit for advanced web development. Has some unique features ;)