I would like to add a high score system and to present the high score to every player out there on the website
and inside the game (like top 10 best players).
what would be the best way to do this?
You'll need programming knowledge on PHP and a hosting server or account.
Luckily some generous and helpful people here on scirra shared their expertise.
Here are the links to the tutorials, you can pick from either one of them: