Javascript and HTML5 use canvas to build a Web backgammon game implementation algorithm_javascript skills

This is just a simple JAVAscript and HTML5 applet, and does not implement human-computer combat.
A two-dimensional array corresponding to the placement points on the backgammon board. The elements of the array correspond to the drop points. For example, an array element value of 0 means that there are no chess pieces at the placement point corresponding to the element, an array element value of 1 means that there are white chess pieces at the placement point corresponding to the element, and an array element value of 2 means that there are black chess pieces at the placement point corresponding to the element;
The algorithm for determining the winning position in backgammon is implemented by operating on the two-dimensional array corresponding to the placement point on the backgammon board.

Algorithm for judging winning in backgammon
The function below can implement the algorithm for judging winning in backgammon, or it can be implemented according to the corresponding algorithm in the textbook.
The parameter xx.yy of the function is the array subscript, and the chess array implements the data structure mapping of the placement points on the backgammon board.
The idea of ​​the algorithm is: use the subscript corresponding to the current placement point as the base point, search in 8 directions around it, if there are five pieces of the same color in a row, return 1, or 2, otherwise return 0. Returning 1 means that the white piece wins, and returning 2 means that the black piece wins. Returning 0 means that no winning data structure status has occurred.