The way I understand it, 'videoToolbar' cannot be null or undefined unless there is a development error where the 'forward' argument that is passed to the function is not a child of the 'videoToolBar' element. I don't believe we code to protect against development errors, that we would expect to find the development errors in testing and fix them. If we were to code against development errors, I would suggest throwing an error here to ensure the error was noticed. But, if this is truly a protection against a development error I suggest removing it.