How do I stop from going into the negatives

Question

If you click “Fight” then “Keep fighting” it will eventually go into the negatives can someone make it go to zero thanks

(Feel free to add your name up top)
https://code.sololearn.com/WcxHstyrj1Ux/?ref=app

Answer 1

https://code.sololearn.com/W7CYVP5jMe80/#js

Answer 2

Can you use an if statement to avoid this? something like:
if (x < ) {
x = 0;
}
Your variable will never go below zero that way.