# When this.root equals null or not!

**URL:** <https://forum.kirupa.com/t/when-this-root-equals-null-or-not/298315>\
**Category:** flash\
**Created:** [October 16, 2009, 11:24am UTC](https://forum.kirupa.com/t/when-this-root-equals-null-or-not/298315 "2009-10-16T11:24:07Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Raabi](https://avatars.discourse-cdn.com/v4/letter/r/41988e/32.png) [@Raabi](https://forum.kirupa.com/u/Raabi)\
**Post date:** [October 16, 2009, 11:24am UTC](https://forum.kirupa.com/t/when-this-root-equals-null-or-not/298315/1 "2009-10-16T11:24:07Z")

</div>

Hello

I have some confusions on **root** and the **stage** classes; like;[LIST=1]  
[_]When should I use root or the stage class, from within my custom classes, in order to access the existing objects on the main timeline.  
[_]When is **this.root** == null or not!  
[\*]How can I check **numChildren** on the main timeline.  
[/LIST]I will highly appreciate any help & guidance on the subject, as a whole or on the mentioned points in particular.