The top level contains the core ActionScript classes and global functions.

 AccessibilityThe Accessibility class manages communication with screen readers.
 argumentsAn arguments object is used to store and access a function's arguments.
 ArrayThe Array class lets you access and manipulate indexed arrays.
 AsBroadcasterProvides event notification and listener management capabilities that you can add to user-defined objects.
 BooleanThe Boolean class is a wrapper object with the same functionality as the standard JavaScript Boolean object.
 ButtonAll button symbols in a SWF file are instances of the Button object.
 CameraThe Camera class is primarily for use with Flash Media Server, but can be used in a limited way without the server.
 ColorDeprecated since Flash Player 8 — The Color class has been deprecated in favor of the flash.geom.ColorTransform class.
 ContextMenuThe ContextMenu class provides runtime control over the items in the Flash Player context menu, which appears when a user right-clicks (Windows) or Control-clicks (Macintosh) on Flash Player.
 ContextMenuItemThe ContextMenuItem class allows you to create custom menu items to display in the Flash Player context menu.
 CustomActionsThe methods of the CustomActions class allow a SWF file playing in the Flash authoring tool to manage any custom actions that are registered with the authoring tool.
 DateThe Date class lets you retrieve date and time values relative to universal time (Greenwich mean time, now called universal time or UTC) or relative to the operating system on which Flash Player is running.
 ErrorContains information about an error that occurred in a script.
 FunctionBoth user-defined and built-in functions in ActionScript are represented by Function objects, which are instances of the Function class.
 KeyThe Key class is a top-level class whose methods and properties you can use without a constructor.
 LoadVarsYou can use the LoadVars class to obtain verification of successful data loading and to monitor download progress.
 LocalConnectionThe LocalConnection class lets you develop SWF files that can send instructions to each other without the use of fscommand() or JavaScript.
 MathThe Math class is a top-level class whose methods and properties you can use without using a constructor.
 MicrophoneThe Microphone class lets you capture audio from a microphone attached to the computer that is running Flash Player.
 MouseThe Mouse class is a top-level class whose properties and methods you can access without using a constructor.
 MovieClipThe methods for the MovieClip class provide the same functionality as actions that target movie clips.
 MovieClipLoaderThis class lets you implement listener callbacks that provide status information while SWF, JPEG, GIF, and PNG files are being loaded into movie clips.
 NetConnectionThe NetConnection class provides the means to play back streaming FLV files from a local drive or HTTP address.
 NetStreamThe NetStream class provides methods and properties for playing Flash Video (FLV) files from the local file system or an HTTP address.
 NumberThe Number class is a simple wrapper object for the Number data type.
 ObjectThe Object class is at the root of the ActionScript class hierarchy.
 PrintJobThe PrintJob class lets you create content and print it to one or more pages.
 SelectionThe Selection class lets you set and control the text field in which the insertion point is located (that is, the field that has focus).
 SharedObjectShared objects offer real-time data sharing between multiple SWF files.
 SoundThe Sound class lets you control sound in a movie.
 StageThe Stage class is a top-level class whose methods, properties, and handlers you can access without using a constructor.
 StringThe String class is a wrapper for the string primitive data type, and provides methods and properties that let you manipulate primitive string value types.
 SystemThe System class contains properties related to certain operations that take place on the user's computer, such as operations with shared objects, local settings for cameras and microphones, and use of the Clipboard.
 TextFieldThe TextField class is used to create areas for text display and input.
 TextFormatThe TextFormat class represents character formatting information.
 TextSnapshotTextSnapshot objects let you work with static text in a movie clip.
 VideoThe Video class enables you to display live streaming video on the Stage without embedding it in your SWF file.
 XMLUse the methods and properties of the XML class to load, parse, send, build, and manipulate XML document trees.
 XMLNodeAn XML document is represented in Flash by the XML class.
 XMLSocketThe XMLSocket class implements client sockets that let the computer running Flash Player communicate with a server computer identified by an IP address or domain name.
 XMLUIThe XMLUI object enables communication with SWF files that are used as custom user interfaces for the Flash authoring tool's extensibility features (such as Behaviors, Commands, Effects, and Tools).