Actionscript 2.0 and Actionscript 3.0 are both coding languages. Adobe developed them, and they can be used for creating games and animations. 2.0 came first, and Adobe wanted to improve 2.0. Instead of changing 2.0, Adobe created 3.0. One of the changes that came with 3.0 is speed 3.0 is ten to fifteen times faster than 2.0. Another upgrade with 3.0 is the way coding is executed. With 2.0, users were able to code faster with ticks to the system to skip certain elements. 3.0 requires the user to use Object-Oriented Programming, which is more time consuming but will make the code cleaner.
AS2 and AS3 are known to be two different languages that run on different virtual machines. Take note that the codes that are available in the AS2 come with AS3 equivalents just in case you would need to work them out together. The main difference between the two is that AS3 will allow you to create a better and more powerful OOP influence especially when this would be compared to AS2.
If there are some codes that are needed to be utilized, the AS3 can also be the better option. It is obvious that the AS3 can be considered to be the upgrade of the AS2 which means that it will offer more features that you will find to be very helpful if in case you need to use them.