Why does it pick heads or tails TWICE randomly? (Code link in description below here)

Question

https://code.sololearn.com/WF2YoX6Jy5KZ/?ref=app

Answer 1

You are added to listeners
1st by inline
2nd by javascript

Answer 2

It seems to be related to the fact that you added the same event twice to the button: once in html, once in js tab.

Answer 3

Thank you! (And you too Brave Tea for trying to help)