There seems to be this misconception that adding ActionScript in the Timeline will not be supported when using AS3. FALSE!!! If you are migrating over from AS2 to AS3, adding ActionScript in the Timeline is probably the least of your concerns.
The concept of inserting ActionScript to control or trigger animations has not changed from AS2 to AS3. While inserting all of your ActionScript code throughout the Timeline is not recommended, doing so will not break any functionality.
There are many other misconceptions dealing with migrating over from AS2 to AS3. Mike Chambers recently spoke on this topic at FlashCamp in London. Unfortunately like most, I was not able to be there. However, Mike has made the slideshow of his presentation available for download. You can see it below.
If you are currently trying to make that switch from AS2 to AS3, what’s stopping you? What’s keeping you up at night? I would love to hear from you if somthing is keeping you up at night.