This program is a JavaScript implementation of the board game [Chess](http://en.wikipedia.org/wiki/Chess), with a computer player opponent. All move types are supported, including en passant, castling and promotion.
Try it out [here](https://chess.entryrise.com). Usage is shown below the chessboard. At least Internet Explorer (8 or later), Chrome and Firefox should work.
*`zobrist.js`: Game state hash calculator. Currently only used for the threefold repetition rule, but will be used in the transposition table implementation.
*`ai.js`: Artificial intelligence, i.e. computer opponent. Basic alpha-beta pruned minimax with a simple evaluation function.
*`ui.js`: User interface code.
*`chess.include.js`: Includes all of the above files.
*`chess.css`: User interface style.
*`chess.ico`: Icon.
*`chess.html`: Main game file.
*`test.js`: Automated tests.
*`test.html`: Automated test runner.
# Building
To compile the minified version using `compile.sh` in the `build` directory, you need [bash](http://git-scm.com/download/win) and the [Closure compiler](https://developers.google.com/closure/compiler/). You may need to adjust the `.jar` location in `compile.sh`. Compiled files are placed in the top-level directory.
To lint using `lint.sh` in the build directory, you need bash and [JavaScript Lint](http://www.javascriptlint.com/). You may need to adjust lint's path in `lint.sh`.
To run the tests, open `test.html` in the `src` directory.
# TODO
* Static exchange evaluation
* Transposition table
* Iterative deepening
* Negamax formulation
* AI randomness
* Take game phase into account in evaluation
* Take mobility into account in evaluation
* Killer heuristic
* Late-check castling legality
* Tie-detection
* Move pieces without drag and drop
* Underpromotion
* Show captured pieces in the UI
* Don't hardcode board target div to UI
* UI for loading game state from parsable Chess notation(s)
The Chess implementation is distributed under the [MIT](https://github.com/kbjorklu/chess/blob/master/LICENSE) license. See accompanying LICENSE file for details.
