# Need answers for Flash AS 3.0 questions

**URL:** <https://forum.kirupa.com/t/need-answers-for-flash-as-3-0-questions/314688>\
**Category:** flash\
**Created:** [October 6, 2010, 11:04am UTC](https://forum.kirupa.com/t/need-answers-for-flash-as-3-0-questions/314688 "2010-10-06T11:04:03Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![rajesh\_flash](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@rajesh\_flash](https://forum.kirupa.com/u/rajesh_flash)\
**Post date:** [October 6, 2010, 11:04am UTC](https://forum.kirupa.com/t/need-answers-for-flash-as-3-0-questions/314688/1 "2010-10-06T11:04:03Z")

</div>

Hello Friends,

I have few questions in Flash AS 3.0. Can some one help me out by providing the answers to me.

- I know what is an Interface, can you please tell me what is the use of interface and what was the main purpose of this.

- I know what is a Singleton Class, can you guys please tell me how to enforce a singleton class. How do we define/declare a singleton class. how do we restrict to create only 1 instance at run time.

- what is the difference between displayObject and displayList in Flash cs3.

- How to extend multiple classes in another class. for ex: classA extends classB,class C. how to do this in flash cs3. is it possible to extend multiple classes in a single class.

- what is 508 compliance testing or what so ever.

- what is a dynamic class and what is the purpose of a dynamic class

you answers will be really appreciated.

Thanks,  
Rajesh