Javascript - move box from current position ( testimonial slider )

Question

I can't figured out how to move the boxes back and forth.

I can move from left to right, but if i try from right to left it goes crazy.

Here you have the code

Here you have the live example

Answer 1

The problem was the output of the box.style.transform.replace(/[^\d]/g, '').

It returned the only the positive number e.g: 100px even if the property value is: translateX(-100px).

The solution was to get the negative value aswell. All i need to do was to change the regex statement.

SOLUTION: box.style.transform.replace(/[^-\d]/g, '').

EXPLANATION: Replace all characters that are NOT - or number / digit.

Code and live example updated.