IMHO such code is easier to read if only the actual thing that will be controlled by the parameter is inside a if-def. Anything that is done the same way should be just once stated, so the reader does not have to compare so many things to see what is the difference.
So I would prefer this code to be:
```
var display = (choice === true) ? "block" :  "none";
overlayTop.style.display = overlayMiddle.style.display = overlayBottom.style.display = display;
isVisible = choice;
```