Fix Javascript error .. Console Output - Uncaught TypeError: Cannot read property 'remove' of undefined

Question

I have created a modal window wherein i can open two modal windows one -by-one and it has functionality to close them similarly one -by-one ( closing second window keeps the earlier window still active )
My JavaScript code has some issue also mentioned in the question title. Please someone suggest a fix
Whole codes + Output present here - https://jsbin.com/kasanaxuta/edit?output

Answer 1

line 39: modals[index].classList.remove("modal-content-active");
You got an error here.
I think it happens, because You wrote a selector ("modal-content-active") incorrect. Try changing it to proper name.