Editing ActionScript (section)

==History==
ActionScript started as an [[object-oriented programming]] language for [[Macromedia]]'s Flash authoring tool, later developed by Adobe Systems as Adobe Flash. The first three versions of the Flash authoring tool provided limited interactivity features. Early Flash developers could attach a simple command, called an "action", to a button or a frame. The set of actions was basic navigation controls, with commands such as "play", "stop", "getURL", and "gotoAndPlay".

With the release of Flash 4 in 1999, this simple set of actions became a small scripting language. New capabilities introduced for Flash 4 included [[variable (programming)|variables]], [[expression (programming)|expressions]], [[operator (programming)|operators]], [[Conditional (programming)|if statements]], and [[Program loops|loops]]. Although referred to internally as "ActionScript", the Flash 4 user manual and marketing documents continued to use the term "actions" to describe this set of commands.

===Timeline by player version===
* '''Flash Player 2''': The first version with scripting support, its actions included gotoAndPlay, gotoAndStop, nextFrame and nextScene for timeline control.
* '''Flash Player 3''': Expanded basic scripting support, it has the ability to load external [[SWF]]s (loadMovie).
* '''Flash Player 4''': The 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.
* '''Flash Player 5''': Included in the first version of ActionScript, it used [[prototype-based programming]] based on ECMAScript,<ref>{{cite web|url=http://www.ecma-international.org/publications/standards/Ecma-262.htm |title=Standard ECMA-262 |publisher=Ecma-international.org |access-date=April 22, 2013}}</ref> and allowed full [[procedural programming]] and object-oriented programming. Design based development.
* '''Flash Player 6''' added an event-handling model, accessibility controls, and support for [[switch statement|switch]]. The first version with support for the [[Action Message Format]] (AMF) and [[Real-Time Messaging Protocol]] (RTMP) allowed for on demand audio/video streaming.
* '''Flash Player 7''': Additions to it include Cascading Style Sheets ([[CSS]]) styling for text and support for ActionScript 2.0, a programming language based on the ECMAScript 4 [[Netscape]] Proposal<ref>{{cite web|url=http://www.mozilla.org/js/language/es4.html |archive-url=https://web.archive.org/web/20070711065258/http://www.mozilla.org/js/language/es4.html |url-status=dead |archive-date=July 11, 2007 |title=ECMAScript 4 Netscape Proposal |publisher=[[Netscape]] |editor=Waldemar Horwat |date=June 30, 2003 |access-date=April 11, 2019}}</ref> with [[Class (computer programming)|class]]-based [[Inheritance (object-oriented programming)|inheritance]]. However, ActionScript 2.0 can [[cross compile]] to ActionScript 1.0 [[bytecode]], so that it can run in Flash Player 6.
* '''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 [[drop shadow]].
* '''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 [[Just-in-time compilation|just-in-time]] (JIT) compiler. Support for binary sockets, [[ECMAScript for XML]] (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.<ref>{{cite web|url=https://www.adobe.com/products/flashplayer |title=Flash Player &#124; Adobe Flash Player 11 &#124; Overview |publisher=Adobe.com |date=April 9, 2013 |access-date=April 22, 2013}}</ref>
* '''Flash Player 10 (initially called Astro)''': Added basic [[3D computer graphics|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]]s, especially with [[H.264]] video. There is a new sound API which allows for custom creation of audio in flash, something that has never been possible before.<ref>{{cite web|url=http://labs.adobe.com/technologies/flashplayer10/ |title=Adobe Labs – Adobe Flash Player 10.1 |publisher=Labs.adobe.com |access-date=December 17, 2009| archive-url= https://web.archive.org/web/20100105125609/http://labs.adobe.com/technologies/flashplayer10/| archive-date= January 5, 2010 | url-status= live}}</ref> Furthermore, Flash Player 10 supports Peer to Peer ([[Peer-to-peer|P2P]]) communication with [[Real Time Media Flow Protocol]] (RTMFP).
* '''Flash Player 11''': The major addition in this version are the [[Stage3D]]-based advanced (graphic card accelerated) 3D capabilities for Windows Desktop, Mac Desktop, [[iOS]], [[Android (operating system)|Android]], and other major platforms. Significant compatibility improvements have been added for the iOS platform, and other non-desktop platforms. Other features include H.264 encoding for cameras, Native [[JSON]] support, [[Bézier curve|Cubic Bézier Curves]], a secure [[random number generator]], [[LZMA]] compression for SWF files, workers to offload some code execution to other processor threads, graphics card accelerated camera feed rendering, memory intrinsics and performance analysis, and the ActionScript Compiler 2.0, as well as some other minor additions.<ref>{{cite web|url=http://download.macromedia.com/pub/labs/flashplatformruntimes/shared/flashplayer11_air3_b1_releasenotes_071311.pdf |archive-url=https://web.archive.org/web/20110714222550/http://download.macromedia.com/pub/labs/flashplatformruntimes/shared/flashplayer11_air3_b1_releasenotes_071311.pdf |url-status=dead |archive-date=2011-07-14 |title=Flash Player 11 and AIR 3 Release Notes for Adobe Labs}}</ref>
* '''Flash Player 11.2''': released in March 2012, focused on adding features that are key for the gaming and video markets. Some of the features in the release include the following: Mouse-lock support. Right and middle mouse-click support. Context menu disabling. Hardware-accelerated graphics/Stage 3D support for Apple iOS and Android via Adobe AIR. Support for more hardware accelerated video cards (from January 2008) in order to expand availability of hardware-accelerated content. New Throttle event API (dispatches event when Flash Player throttles, pauses, or resumes content). Multithreaded video decoding pipeline on PCs, which improves overall performance of video on all desktop platforms. Notification of use of premium features in the debug players; content runs unrestricted in the release players.
* '''Flash Player 11.3''': released in June 2012, focused on enabling features and functionality key for the gaming market, as well as addressing popular feature requests from developers. Some of the features in this release include the following: Keyboard input support in full-screen mode. Improved audio support for working with low-latency audio. Ability to progressively stream textures for Stage 3D content. [[Protected mode]] for Flash Player in [[Firefox]]. Frame label events. Support for compressing BitmapData to [[JPEG]] and [[PNG]] formats. Support for [[Mac OS X]] [[Mac App Store|App Store]] application sandboxing requirements. Text streaming support for Stage 3D. Expanded information about GPU [[device driver|driver]] details. Bitmap draw with quality API (new). Release outside mouse event API. Flash Player silent update support for Mac OS. Stylus support for Android 4.0 devices (Adobe AIR). USB debugging for iOS (Adobe AIR). iOS simulator support (Adobe AIR).
* '''Flash Player 11.4''': Released in August 2012, it focused on enabling features and functionality that are key for the gaming market, as well as addressing popular feature requests from developers. Some of the features in this release include ActionScript workers (enables concurrent ActionScript execution on separate threads), support for advanced profiling, [[LZMA]] compression support for ByteArray, support for hardware-accelerated video cards for Stage 3D expanded to 2006, improved ActionScript performance when targeting Apple iOS, performance index API to inform about performance capabilities of current environment, support for compressed textures with alpha support, support for StageVideo.attachCamera API, and support for push notifications for iOS (Adobe AIR).
* '''Flash Player 11.5''': Released in November 2012, it focused on performance improvement and stability. Some of the features in this release include shared ByteArray support for ActionScript workers, debug [[stack trace]] in release builds of Flash Player, and various bug fixes.
* '''Flash Player 11.6''': Released in March 2013, it focuses on performance improvements, security enhancements, and stability. Some of the features in this release include ability to query graphics vector data at runtime, full-screen permission dialog user interface improvements, ability to load SWFs at runtime when deploying as an AIR application in AOT mode on iOS, finer-grained control over supported display resolution on iOS devices when deploying as an AIR application, HiDPI support for Flash Professional, and ActionScript 3 access to fast memory operations/intrinsics.
* '''Flash Player 11.7''': Released in June 2013, code-named "Geary", this release focuses on premium video, gaming, security, and stability. Some of the features planned for this release include Android captive runtime debugging, support for the [[Ouya|OUYA]] controller, remote hosting of SWF files on iOS, and preventing backup of shared objects on iOS for better iCloud support.
* '''Flash Player 11.8''': Adobe was planning to release this version in the early part of the second half of 2013, code-named "Harrison". This release focused on premium video, gaming, security, and stability. Some of the features in this release would have included recursive stop API on MovieClips and GamePad support on desktop browsers and Android.

===Timeline by ActionScript version===
====2000–2004: ActionScript "1.0" ====
With the release of Flash 5 in September 2000, the "actions" from Flash 4 were enhanced once more and named "ActionScript" for the first time.<ref>{{Cite web|url=https://helpx.adobe.com/x-productkb/multi/release-notes-flash-player-11.html|title=Flash Player 11, AIR 3 Release Notes|website=helpx.adobe.com|access-date=2016-10-07}}</ref> This was the first version of ActionScript with influences from [[JavaScript]] and the [[ECMA-262]] (Third Edition) standard, supporting the said standard's object model and many of its core [[data type]]s. Local variables may be declared with the {{Mono|var}} statement, and user-defined [[function (computer science)|functions]] with [[parameter (computer science)|parameter]] passing and [[return statement|return]] values can also be created. Notably, ActionScript could now also be typed with a text editor rather than being assembled by choosing actions from drop-down lists and dialog box controls. With the next release of its authoring tool, Flash MX, and its corresponding player, [[Adobe Flash Player|Flash Player 6]], the language remained essentially unchanged; there were only minor changes, such as the addition of the {{Mono|switch}} statement and the "strict equality" ({{Mono|1====}}) operator, which brought it closer to being [[ECMA-262]]-compliant. Two important features of ActionScript that distinguish it from later versions are its loose type system and its reliance on prototype-based [[inheritance (object-oriented programming)|inheritance]]. Loose typing refers to the ability of a [[variable (programming)|variable]] to hold any type of data. This allows for rapid script development and is particularly well-suited for small-scale scripting projects. Prototype-based inheritance is the ActionScript 1.0 mechanism for code reuse and object-oriented programming. Instead of a {{Mono|class}} keyword that defines common characteristics of a [[class (computer science)|class]], ActionScript 1.0 uses a special object that serves as a "prototype" for a class of objects. All common characteristics of a class are defined in the class's prototype object and every [[Instantiation (computer science)|instance]] of that class contains a link to that prototype object.

====2003–2006: ActionScript 2.0 ====
The next major revision of the language, ActionScript 2.0, was introduced in September 2003 with the release of Flash MX 2004 and its corresponding player, [[Adobe Flash Player|Flash Player 7]]. In response to user demand for a language better equipped for larger and more complex applications, ActionScript 2.0 featured compile-time [[type checking]] and class-based [[syntax of programming languages|syntax]], such as the keywords {{Mono|class}} and {{Mono|extends}}. While this allowed for a more structured object-oriented programming approach, the code would still be compiled to ActionScript 1.0 [[bytecode]], allowing it to be used on the preceding Flash Player 6 as well. In other words, the [[Class-based programming|class-based]] inheritance syntax was a layer on top of the existing prototype-based system. With ActionScript 2.0, developers could constrain [[variable (programming)|variables]] to a specific type by adding a type annotation so that type mismatch errors could be found at [[compile-time]]. ActionScript 2.0 also introduced class-based inheritance syntax so that developers could create classes and interfaces, much as they would in class-based languages such as [[Java (programming language)|Java]] and [[C++]]. This version conformed partially to the [[ECMAScript]] Fourth Edition draft specification.

====2006–2020: ActionScript 3.0====
In June 2006, ActionScript 3.0 debuted with [[Adobe Flex|Adobe Flex 2.0]] and its corresponding player, [[Adobe Flash Player|Flash Player 9]]. ActionScript 3.0 was a fundamental restructuring of the language, so much so that it uses an entirely different [[virtual machine]]. Flash Player 9 contains two virtual machines, AVM1 for code written in ActionScript 1.0 and 2.0, and AVM2 for content written in ActionScript 3.0. ActionScript 3.0 added limited support for [[hardware acceleration]] ([[DirectX]], [[OpenGL]]).

The update to the language introduced several new features:
* [[Compile-time]] and [[Run time (program lifecycle phase)|run-time]] type checking—type information exists at both compile-time and runtime.
* Improved performance from a class-based inheritance system separate from the prototype-based inheritance system.
* Support for [[Java package|packages]], [[namespace]]s, and [[regular expressions]].
* Compiles to an entirely new type of [[bytecode]], incompatible with ActionScript 1.0 and 2.0 bytecode.
* Revised Flash Player [[API]], organized into [[Java package|packages]].
* Unified [[event handling]] system based on the [[DOM Events|DOM event handling]] standard.
* Integration of [[ECMAScript for XML]] (E4X) for purposes of [[XML]] processing.
* Direct access to the Flash [[run-time system|runtime]] display list for complete control of what gets displayed at runtime.
* Completely conforming implementation of the [[ECMAScript]] fourth edition draft specification.
* Limited support for dynamic 3D objects. (X, Y, Z rotation, and texture mapping)

===Flash Lite===
* '''[[Flash Lite]] 1.0''': Flash Lite is the Flash technology specifically developed for mobile phones and consumer electronics devices. Supports Flash 4 ActionScript.
* '''Flash Lite 1.1''': Flash 4 ActionScript support and additional device APIs added.
* '''Flash Lite 2.0 and 2.1''': Added support for Flash 7 ActionScript 2.0 and some additional fscommand2 API.
* '''Flash Lite 3''': Added support for Flash 8 ActionScript 2.0 and also [[FLV]] video playback.
* '''Flash Lite 4''': Added support for Flash 10 ActionScript 3.0 as a browser plugin and also hardware graphics acceleration.

===AIR===
[[Adobe AIR]] supports ActionScript, in addition to some extended contents, such as the Stage3D engine Adobe has developed. The number of [[API]]s (Application programming interfaces) available to ActionScript 3.0 has also risen dramatically.