Watch for changes in variables

How can I ‘watch’ for changes in the _width, scroll, maxscroll properties other than onEnterFrame / setInterval etc. Btw. I tryed <object>.watch but found this in the AS ref:

"Generally, predefined ActionScript properties, such as _x, _y, _width, and _height, are getter/setter properties and cannot be watched with Object.watch(). "

Why do I need this? Im making a dynamic textfield with a scrollbar that will display loaded text, but here’s the catch. The site is on a single frame, and has a button that uses a resizeTo() function (a Flash extension) on the textfield and changes it’s _width value. So thats why I need to update these values for the scrollbar to be accurate.

I’ve searched the forum, in hopes that somebody have made something like this before, but no luck ; (.

Thanks for the help.