Antonioss

hi there, i am new in javascript, i am following the w3schools tutorials for making a game to be specific this tutorial http://www.w3schools.com/games/tryit.asp?filename=trygame_gravity_game but i need help to add a pause function , i have tried a few things but nothing. i dont know if i have to add Time and loop, or if this can be done only with Frame No. Thank you