The user can interact with the pgn4web chessboard using the keyboard or clicking chessboard squares; hovering the mouse on each square displays an help summary.
A search tool allows searching within the PGN games.
Errors alert messages are logged, such as failures to load PGN games, incorrect PGN games or incorrect FEN strings. When an error is encountered, the top left chessboard square will flash to signal the exception. The error alert log can be reviewed clicking on the same top left chessboard square.
For full details about the search tool (implemented as regular expression match of the text of the PGN game), please refer to the pgn4web search tool wiki page; please find below a sample list of useful search patterns:
PNG images from http://ixian.com/chess/jin-piece-sets by Eric De Mund; licensed under creative commons attribution-share alike 3.0 unported license.
SVG images from http://commons.wikimedia.org/wiki/Category:SVG_chess_pieces by Colin M.L. Burnett; licensed under GFDL, CC-BY-SA-3.0 or GPL, via Wikimedia Commons.
The figurine fonts are derived from the Liberation Sans font (released under GNU General Public License, see https://fedorahosted.org/liberation-fonts/) with the addition of chess pieces from freeware fonts: the alpha2 font (Peter Strickland), the good companion font (David L. Brown), the merida font (Armando H. Marroquin), the pirate font (Klaus Wolf) and the chess usual font (Armando H. Marroquin). The original chess fonts and more details are available at http://www.enpassant.dk/chess/fonteng.htm
Remaining pgn4web code is copyright (C) 2009, 2011 Paolo Casaschi (email@example.com) and licensed under the terms of the GNU General Public License version 2 as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.