Scrollbar component

I was just wondering, (I haven’t checked yet) if there is a variable in the scrollbar component that could be used to determine the lenght of text.

I want to be able to either turn the visibility/alpha of the component off, if the text used is not larger than the text box itself.

So say if I had a large text box with changing content, sometimes the content would not spill over and need a scroll bar, if that was the case make the component not visible.