This is a JS chess implementation. (OLD) I have turned this into a multiplayer site at https://chess.oggyp.com. Single player at https://chess.oggyp.com/game. It accurately detects legal moves and supports exporting to PGN. On my website it also supports PGN import. You are also able to flip the board.
Click a piece and then click on one of the tiles that are shown with a dot. It is simple to use, however there is no drag and drop. I was unsure how to add drag and drop but I would like to.