@MessyAswer "... I haven't been able to find a way to make a custom variant. What do I have to do?"
Well, in the current setup it is something I would have to do. The variant is defined in the HTML of the web page; a JavaScript program shared by all such web pages reads the definition, and creates the interactive chessboard diagram from it. It also takes care of the communication with a CGI program on the server, responsible for storing and retrieving moves, subject to user identification. The only thing configurable by the user is that he can alter the moves of the participating pieces, as used for genrating the highlights (underneath the piece legend). But as he would have todo that every time he reloads the page, that is not really a viable method for defining his own variants.
But this is relatively easy to remedy. I already have programmed a 'wizard' in JavaScript to help people to create a diagram definition for arbitrary variants (see http://www.chessvariants.com/index/msdisplay.php?itemid=MSinteractive-diagrams ). This is now set up to produce the diagram definition as HTML text, for people to paste it in their own web pages. It can be easily modified to store that definition as the first part of a game file, though. Then a 'universal' turn-based server page could not have a predefined diagram for a fixed variant, but create the diagram from the description in the game file, every time a game is loaded.
Then visitors of the web page could either recall an existing game to use its game definition, or use the wizard to define a new game. After that they can start a game in that variant against an opponent.
"However, it would be nice if there was a way to put down / remove pieces from the board (so you could play variants like crazyhouse and atomic chess). "
This exists. At least for dropping the pieces. One of the configuration parameters of the diagram is the 'holdings type'. Depending on its setting captured pieces will be transferred to the table next to the board (as counts next to the pieces), and when the counts are non-zero, the diagram allows you to drag the corresponding piece from the table to the board.
Currently the only way to remove pieces from the board is to capture them. But that actually is good enough. The diagram does not restrict you to move only a single piece per turn. (This was done to make it easy to do non-standard castlings and such.) So to apply an atomic capture you can jump around with the capturing piece to capture everything that would be destroyed in the explosion, and then finally capture it with an opponent piece and move that back. (The diagram also doesn't object against you movig opponent pieces.) Of course if you would really want to play variants like that, it would be more user-friendly to add piece explosions to the capabilities that can be selected from the diagram.
Well, in the current setup it is something I would have to do. The variant is defined in the HTML of the web page; a JavaScript program shared by all such web pages reads the definition, and creates the interactive chessboard diagram from it. It also takes care of the communication with a CGI program on the server, responsible for storing and retrieving moves, subject to user identification. The only thing configurable by the user is that he can alter the moves of the participating pieces, as used for genrating the highlights (underneath the piece legend). But as he would have todo that every time he reloads the page, that is not really a viable method for defining his own variants.
But this is relatively easy to remedy. I already have programmed a 'wizard' in JavaScript to help people to create a diagram definition for arbitrary variants (see http://www.chessvariants.com/index/msdisplay.php?itemid=MSinteractive-diagrams ). This is now set up to produce the diagram definition as HTML text, for people to paste it in their own web pages. It can be easily modified to store that definition as the first part of a game file, though. Then a 'universal' turn-based server page could not have a predefined diagram for a fixed variant, but create the diagram from the description in the game file, every time a game is loaded.
Then visitors of the web page could either recall an existing game to use its game definition, or use the wizard to define a new game. After that they can start a game in that variant against an opponent.
"However, it would be nice if there was a way to put down / remove pieces from the board (so you could play variants like crazyhouse and atomic chess). "
This exists. At least for dropping the pieces. One of the configuration parameters of the diagram is the 'holdings type'. Depending on its setting captured pieces will be transferred to the table next to the board (as counts next to the pieces), and when the counts are non-zero, the diagram allows you to drag the corresponding piece from the table to the board.
Currently the only way to remove pieces from the board is to capture them. But that actually is good enough. The diagram does not restrict you to move only a single piece per turn. (This was done to make it easy to do non-standard castlings and such.) So to apply an atomic capture you can jump around with the capturing piece to capture everything that would be destroyed in the explosion, and then finally capture it with an opponent piece and move that back. (The diagram also doesn't object against you movig opponent pieces.) Of course if you would really want to play variants like that, it would be more user-friendly to add piece explosions to the capabilities that can be selected from the diagram.