Issues using JavaScript to send Quiz Results to PHP script

Hi all,

So I'm at a point, where I really cannot find the solution.

I have a JavaScript trigger, which should send the scorepoints to my MySQL database:

The PHP script send.php is capturing the userId and quizId correctly, but score output is null.

When I use static values, it works completely fine:

I think I can narrow down the issue with the score variable. I have checked and double checked the variable is correct:

So is it this part that is incorrect, or is there something else I'm missing here?