by Yuki Kimura

ActionScript is an ECMAScript-based programming language used for scripting Adobe Flash movies and applications.
(retrieved from Wikipedia, http://en.wikipedia.org/wiki/ActionScript)

Action Script can incredibly decrease the number of frames and data size.

Imagine that without Action Script, you want make an object move from one side to the other on a stage, you will need at least 10 frames to make the movement look natural, or even more.

However, with Action Script, you can move an object using only one frame and even draw a simple object like a square within the frame, that is you never draw on a stage which also decreases the size of data.

In addition, you have more control over the frame using Action Script, it means you can create any flexible movement on just one frame.

This is an Action Script for a simple movement.

onEnterFrame = function () {

instance name._x -= 10;

};

The onEnterFrame handler executes the function written inside the block.
Here is;

instance name._x -= 10;

Let me explain about the instance name. To make an object move, you first need to put the object into the Library and then the object becomes an instance. To control the instance, you must assign a name for it.

The code which follows the instance name implys changing the x axis by substracting 10 pixels, means the instance moves horizontally.

To summarize, this code commands to move the instance towards left by 10 pixels when the frame is entered.