Chess
Javascript has poor native support for chess. Nor is it fast. Thus many attempts at writing a javascript chessboard failed in the past years.
Now two libraries made the news: the excellent chess.js, which features support for FEN, PGN, legal moves, checkmate conditions and much more.
Chessboard.js on the other hand presents a board.
The two can be integrated easily. To make this task trivial I wrote the idea.js jQuery plugin that does just that: and connects to the ideachess.com server to present chess problems.
This would have not been possible with these great libraries:
Gianluca Cisana
All server code on ideachess
http://ideachess.com
chess.js by Jeff Hlywa
powers the local game logic
https://github.com/jhlywa/chess.js
chessboard.js by Chris Oakman
manages the board
http://chessboardjs.com/
jQuery
http://jquery.com
jQuery.scrollintoview by Robert Koritnik
to scroll solutions easily
https://github.com/litera/jquery-scrollintoview
base64_decode by Kevin van Zonneveld
to overcome IE's lack of atob function.
http://kevin.vanzonneveld.net