Hide input caption when typing with Javascript

I'm trying to hide a default Squarespace form caption type when typing with Javascript yet it doesn't seem to work. This must be an issue you must have run into previously. Would really appreciate your help!

Here's my Js bit embeded in the code

const captionBox = document.querySelector(".caption")
captionBox.addEventListener("click", hideCaption);

function hideCaption () {
    const fields = document.querySelectorAll(".field-element")
    const captionText = document.querySelector(".caption-text")    
    fields.forEach(field => {
        if (field.classList.contains("focus-visible")) {
          captionText.style.visibility = "hidden";
        } else {
          captionText.style.visibility = "visible";
        }
    })
}

Have you wrap code in script tag yet?