Not a bad effort for a first game, try googling 'better jump mechanics' for some alternative was to code the jumping mechanic. If jumping is the main mechanic of the game its worth putting more time into making it as smooth and fun as possible. 

Your game is pretty fun. I like how more fireballs spawn each time. It gets harder and harder as you attempt to get a higher score each time. The only complaint I have with this game is that there is no restart button. It is a bit annoying having to reload the page every time.

I enjoyed playing your game a lot. I liked the increasing difficulty with the number of fireballs jumping around the most. Thank you.

Hello everyone. I'm sorry for this situation, but it's my first game. Next time I'll try to make it better from the start.  I made a new project and now it's working. 

Link: https://proximacentauri1.itch.io/the-7-game-fixed-version-v1

If you want to help me improve please give my your feedback here.