see the code at the GitHub.
https://github.com/prembhaskal/sokoban
play the game live here
http://prembhaskal.github.io/sokoban/
search for sokoban craze on chrome app store to get the game on your PC.
https://chrome.google.com/webstore/detail/sokoban-craze/mnjhkeonmdibdchkpnhgibmogbogmfmj?utm_source=chrome-ntp-icon