So the first thing you may have noticed is that everything in AS2 that had an underscore in front of it no longer does in AS3. That is a MAJOR issues for all of us lazy coders that just want to copy and paste old AS 2 code into an AS3 document – it will fire all sorts of errors such as this one:

Warning: 1058: Migration issue: The property _x is no longer supported.  Use the DisplayObject.x property instead.

So lets say you have a FLA with a MovieClip on the Stage with an instance name of tester_mc and you want to set its x position to 89.

In AS2:

tester_mc._x = 89;

In AS3:

tester_mc.x = 89;

Another little tidbit to keep in mind is that all values that ran from 1 to 100 such as the alpha setting are now running from 0 to 1. If we use the same MovieClip from the last example and set it’s opacity to 50% here is the syntax (remembering to drop the underscore!).


tester_mc._alpha = 50;


tester_mc.alpha = 0.5

These are very simple changes but they have a major impact if you miss one – your program will not run and eventually you will go crazy and want to fight the elderly.

Since we’re on the topic of errors, I have been working to document all of my encounters with both compiler and runtime errors in Flash.

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