ActionScript is an object-oriented programming language originally developed by Macromedia Inc. (since merged into Adobe Systems). It is a derivation of HyperTalk, the scripting language for HyperCard. It is now a dialect of ECMAScript (meaning it is a superset of the syntax and semantics of the language more widely known as JavaScript), though it originally arose as a sibling, both being influenced by HyperTalk.
ActionScript is used primarily for the development of websites and software targeting the Adobe Flash Player platform, used on Web pages in the form of embedded SWF files.
ActionScript 3 is also used with Adobe AIR system for the development of desktop and mobile applications. The language itself is open-source in that its specification is offered free of charge and both an open source compiler (as part of Apache Flex) and open source virtual machine (Mozilla Tamarin) are available.
ActionScript is also used with Scaleform GFx for the development of 3D video game user interfaces and HUDs.
ActionScript was initially designed for controlling simple 2D vector animations made in Adobe Flash (formerly Macromedia Flash). Initially focused on animation, early versions of Flash content offered few interactivity features and thus had very limited scripting capability. Later versions added functionality allowing for the creation of Web-based games and rich Internet applications with streaming media (such as video and audio). Today, ActionScript is suitable for mobile development through Adobe AIR, use in some database applications, and in basic robotics, as with the Make Controller Kit.
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Flash Player 2: The first version with scripting support. Actions included gotoAndPlay, gotoAndStop, nextFrame and nextScene for timeline control.
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Flash Player 3: Expanded basic scripting support with the ability to load external SWFs (loadMovie).
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Flash Player 4: First player with a full scripting implementation (called Actions). The scripting was a flash based syntax and contained support for loops, conditionals, variables and other basic language constructs.
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Flash Player 5: Included the first version of ActionScript. Used prototype-based programming based on ECMAScript, and allowed full procedural programming and object-oriented programming. Design based development.
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Flash Player 6: Added an event handling model, accessibility controls and support for switch. The first version with support for the AMF and protocols which allowed for on demand audio/video streaming.
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Flash Player 7: Additions include CSS styling for text and support for ActionScript 2.0, a programming language based on the ECMAScript 4 Netscape Proposal with class-based inheritance. However, ActionScript 2.0 can cross compile to ActionScript 1.0 byte-code, so that it can run in Flash Player 6.
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Flash Player 8: Further extended ActionScript 1/ActionScript 2 by adding new class libraries with APIs for controlling bitmap data at run-time, file uploads and live filters for blur and dropshadow.
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Flash Player 9 (initially called 8.5): Added ActionScript 3.0 with the advent of a new virtual machine, called ActionScript Virtual Machine 2 (AVM2), which coexists with the previous AVM1 needed to support legacy content. Performance increases were a major objective for this release of the player including a new JIT compiler. Support for binary sockets, E4X XML parsing, full-screen mode and Regular Expressions were added. This is the first release of the player to be titled Adobe Flash Player.
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Flash Player 10 (initially called Astro): Added basic 3D manipulation, such as rotating on the X, Y, and Z axis, a 3D drawing API, and texture mapping. Ability to create custom filters using Adobe Pixel Bender. Several visual processing tasks are now offloaded to the GPU which gives a noticeable decrease to rendering time for each frame, resulting in higher frame rate
