the chess games viewer extension for google chrome

warning: the chess games viewer extension for google chrome has been discontinued

Questionable design choices from the developers of google chrome introduced fundamental changes in the architecture of google chrome extensions, regrettably breaking backward compatibility; these changes require a complete rewriting of the extension's code; the pgn4web project is not interested in such a major undertaking, providing no new features to the end users; also there's no guarantee against future changes once again breaking backward compatibility. As a result, the chess games viewer extension for google chrome has been discontinued by the pgn4web project as of October 2012.

The last available version of the chess games viewer extension for google chrome is still avaibale for download, however it is deprecated and it does not work anymore with the latest version of google chrome.

The support information below is thus obsolete and it is kept only for historical reasons.

The chess games viewer extension for the google chrome browser provides an interactive chessboard showing chess games from links to PGN URLs, from local PGN files and from PGN text, using page actions and context menus.

If you are using google chrome and you don't want to read any further, click here to install the chess games viewer extension (you might have to read this to workaround some odd behaviour of recent versions of google chrome).

features

• The extension looks for links to PGN chess games URLs in visited pages; if found, a page action icon in the address bar allows for opening the links in the chess games viewer.
• A context menu shows chess games from links to PGN chess games URLs; the mouse cursor icon highlights links to PGN chess games URLs when hovering on them.
• The live refresh option reloads the games periodically until all games are ended; use for links to chess games live broadcasts; a single large chessboard view is offered as well as a view with multiple small chessboards.
• A context menu for links to ZIP archives offers to inspect each ZIP archive for PGN chess games; please note: loading ZIP archives is a slow process; only the deflate and store compression methods are supported; encryption is not supported.
• A context menu allows showing chess games from local PGN files and local ZIP archives containing PGN files; the context menu opens the large chessboard view page, click the command files at the top right of the page to open local files or drag and drop local files on the page.
• A context menu shows chess games from PGN chess games text selected in the web page. FEN position strings are also a valid text input.
• Chrome os file browser integration: viewing chess games from PGN files and inspecting ZIP files for chess games.
• Chess game analysis, using the GarboChess engine licensed by Gary Linscott; from the single large chessboard view, click square H2 to toggle the chess game analysis or click square G2 for automatic game annotation.
• Endgame tablebase support using John Tamplin's webservice; from the single large chessboard view, click square F2 to probe the online endgame tablebase about the current position.

As with every pgn4web implementation, click on the viewer's chessboard top right square for user interface help, credits and license; the top left chessboard square will flash in case of PGN data errors, click that square for further details.

The extension is available from the downloads page.

screenshot

installation and updates

The extension supports the current stable version of google chrome. When new features are introduced, newer versions of the extension might not work with versions of google chrome older than the current stable version; the extension installation process should detect the issue and abort the installation.

• the latest release of the chess games viewer supports the current stable version of google chrome: click here to install the latest release
• if you are using an old version of google chrome not supported by the latest release of the chess games viewer, these older releases are recommended:
  • release 1.8.5 of the chess games viewer supports google chrome version 7 to 13
  • release 1.4.7 of the chess games viewer supports google chrome version 6

Unless google chrome breaks backward compatibility, the extension should also work with the latest beta/development/canary versions of google chrome.

Click here to install the chess games viewer extension (you might have to read this to workaround some odd behaviour of recent versions of google chrome: manually open the google chrome extensions page then drag and drop the downloaded file from the download bar into the extensions page).

The extension supports auto-updates and should automatically update to the latest supported version.

In order to take full advantage of the chess figurine fonts, it's strongly recommended to activate the smooth fonts display feature of the operating system.

usage example

Once you have installed the extension, a built-in help file provides a number of usage examples. In order to access the built-in help file, open the google chrome extensions management page from the wrench menu and click on the options link associated to the chess games viewer. Then click on the help heading of the page that opened, that contains detailed instructions with usage examples in the practice sections. Alternative examples are available below in the remaining of this paragraph.

Once you have installed the extension, reload this page. An icon should appear in the address bar of this page, having recognized this link to chess games in PGN format; hovering the mouse over the link, the mouse pointer icon should highlight the link as chess games; manually right-clicking that link the chess games viewer context menu item should be available; finally, you can select the following PGN text and load the game in the chess viewer using the right-click context menu:

[Event "Wch"]
[Site "Moscow URS"]
[Date "1985.10.15"]
[Round "16"]
[White "Karpov"]
[Black "Kasparov"]
[Result "0-1"]
[Opening "Sicilian"]
[ECO "B44"]

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nb5 d6 6. c4 Nf6 7. N1c3 a6 8.
Na3 d5 9. cxd5 exd5 10. exd5 Nb4 11. Be2 Bc5 12. O-O O-O 13. Bf3 Bf5 14.
Bg5 Re8 15. Qd2 b5 16. Rad1 Nd3 17. Nab1 h6 18. Bh4 b4 19. Na4 Bd6 20. Bg3
Rc8 21. b3 g5 22. Bxd6 Qxd6 23. g3 Nd7 24. Bg2 Qf6 25. a3 a5 26. axb4 axb4
27. Qa2 Bg6 28. d6 g4 29. Qd2 Kg7 30. f3 Qxd6 31. fxg4 Qd4+ 32. Kh1 Nf6 33.
Rf4 Ne4 34. Qxd3 Nf2+ 35. Rxf2 Bxd3 36. Rfd2 Qe3 37. Rxd3 Rc1 38. Nb2 Qf2
39. Nd2 Rxd1+ 40. Nxd1 Re1+ 0-1

FEN position strings are also a valid text input:

r1bqkb1r/1p3ppp/p1n1pn2/3p4/2P1P3/N1N5/PP3PPP/R1BQKB1R w KQkq - 0 9

Please find below some other links to practice with the extension:

• these PGN links should trigger the extension, create a context menu that opens the viewer, change the mouse pointer and appear in the page action popup page
  • demoGames.pgn
  • lon09r5.pgn
  • tilb98r2.pgn
• this link to a ZIP file should trigger the extension and create a context menu that opens the viewer but it should not change the mouse pointer nor appear in the page action popup menu
  • zipped.zip

tip: if you often browse local PGN files with the chess games viewer extension, you can place a shortcut on your bookmarks bar for easy access; select the "Open local PGN chess games for viewing on a single board" option of the context menu and bookmark the resulting page; similarly, you could bookmark a live page view for the duration of a tournament (assuming the PGN URL wont change between rounds).

frequently asked questions

How do I know in detail what the chess games viewer can do?

A detailed instructions page with usage examples is available clicking square A7 (assuming White on bottom) or selecting the options page from the google chrome extension management page. Click square H8 (assuming White on bottom) for the general pgn4web interface help (about shortcut squares, shortcut keys and search tool).

The chessboard is too small (large) for my very big (small) screen. How do I change the chessboard size?

Use the zoom feature of google chrome (wrench menu, zoom item) to resize the chessboard page. google chrome will remember the chosen zoom level.

How to switch between the single large chessboard view and the smaller multiple chessboards view?

When in live broadcast mode, click square H5 (assuming White on bottom) to switch view. Option only available in live broadcast mode.

What is the meaning of the numbers on the window title during a live broadcast?

During a live broadcast, the window title contains a set of three numbers, like "1.2.3 live broadcast" where the first number increases each time a new move is received for the visible games (acting as new move notification), the second is the overall number of live games and the third is the overall number of games.

How to view chess games from a local PGN file?

Start by opening the chess games viewer single large chessboard page by right clicking any web page, a real web page though, like google.com, the chrome new tab page wont work for this. On the context menu select the "chess games viewer" item and then the "Open local PGN chess games FILES...". Bookmark the single large chessboard page for easier access later. A local PGN file can be viewed by using the command files at the top right of the single large chessboard page or by drag and drop on the single large chessboard page.

How can I use the extension's chessboard to play a game against a friend or against the computer?

The chess games viewer extension is, by name, only a viewer. You can view games and annotate games with the embedded chess engine, but you can not play a game against a friend or against the computer. For game playing the best suggestion is to play with a friend on a real chessboard; alternatively to play other people online at freechess.org and as last resort to play with an online computer opponent such as GarboChess.

What is the Elo rating of the analysis engine?

I have no idea. If you really care about Elo ratings, you probably should use a commercial engine optimized for your computing platform.

Sometimes the text on the chessboard pages appears garbled; how to avoid that?

For some unknown reason, on rare occasions the text on the chessboard pages appears garbled; simply reloading the page (and reloading the PGN input if necessary) usually fixes the problem.

Why this extension is not available from the google chrome web store?

The use of the google chrome web store requires developers to release full control over the extensions and their encryption keys to the web store; in return, extensions gets more exposure to google chrome users, likely resulting in more installations. However such a mass market advertisement is not valuable for a very specialized extensions tailored to experienced chess players (as opposed to a chess playing extension for casual chess players); instead, the pgn4web project relies on word of mouth among fellow chess players to reach target users: if you like the chess games viewer extension for google chrome recommend it to your chess friends!

users' feedback

Feedback about the chess games viewer extension is welcome, especially ideas for additional functionality, bugs reports and links to any sites hosting chess games that are not captured and displayed properly by the extension.

Feel free to leave feedback in the comment section below, to add an entry into the project issue list or emailing pgn4web@casaschi.net