I need help

I am not a great coder, just a new dude. I have a project where I would need to type smth in like: if(a===b){ x+=1 }. The problem is, that it should just happens ones, so if a = b for a longer time x should not get highter. X have to become + 1 at the begging and than it will only works after (!a===b) and than (a===b) again.
Pls help me, AI can´t help me at all : /
Thanks