Movieclip property listener

I’d like to know when a property of a movieclip changes to fire a function, instead of having an onEnterFrame.

For example knowing when _width changes and moving another movieclip according to the new _width value.

I’ve googled and no one seems to have this problem in any forum… :puzzle:

I don’t know how to set a listener to a variable or a property… :puzzle:

I’ve tried with with no results… :puzzle:

The manual says

Generally, predefined ActionScript properties, such as _x, _y, _width, and _height, are getter/setter properties and cannot be watched with

I know get/set are OOP concepts but I don’t really understand how can get/set help me with that. (I’m a designer…)

Any help is appreciated. TIA! :wink: