# Movieclip property listener

**URL:** <https://forum.kirupa.com/t/movieclip-property-listener/247435>\
**Category:** Uncategorized\
**Created:** [December 23, 2007, 4:06pm UTC](https://forum.kirupa.com/t/movieclip-property-listener/247435 "2007-12-23T16:06:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Pier25](https://avatars.discourse-cdn.com/v4/letter/p/4af34b/32.png) [@Pier25](https://forum.kirupa.com/u/Pier25)\
**Post date:** [December 23, 2007, 4:06pm UTC](https://forum.kirupa.com/t/movieclip-property-listener/247435/1 "2007-12-23T16:06:56Z")

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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 object.watch 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 Object.watch()

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! 😉