Cocos creator web-mobile build google login issue

hi,
i am trying to implement google login on the web-mobile build of my game and i don’t want to use google-play-game-service for that purpose. can someone please guide me as to how to achieve this?
basically i already have a web-version of my game but without using google-play-game-services i want the player to be able to login through their google account.
please help.
thanks!