ActiveX

ActiveX is a software framework created by Microsoft that adapts its earlier Component Object Model (COM) and Object Linking and Embedding (OLE) technologies for content downloaded from a network, particularly in the context of the World Wide Web.^[1] It was introduced in 1996 and is commonly used in its Windows operating system. In principle it is not dependent on Microsoft Windows, but in practice, most ActiveX controls require either Microsoft Windows or a Windows emulator. Most also require the client to be running on Intel x86 hardware, because they contain compiled code.^[2]

Many Microsoft Windows applications — including many of those from Microsoft itself, such as Internet Explorer, Microsoft Office, Microsoft Visual Studio, and Windows Media Player — use ActiveX controls to build their feature-set and also encapsulate their own functionality as ActiveX controls which can then be embedded into other applications. Internet Explorer also allows the embedding of ActiveX controls in web pages. However, ActiveX will not work on all internet platforms, so using ActiveX controls to implement essential functionality of a web page restricts its usefulness.

History

Faced with the complexity of OLE 2.0 and with poor support for COM in MFC, Microsoft simplified the specification and rebranded the technology as ActiveX in 1996.^[3][4] Even after simplification, users still required controls to implement about six core interfaces. In response to this complexity, Microsoft produced wizards, ATL base classes, macros and C++ language extensions to make it simpler to write controls.

Starting with Internet Explorer 3.0 (1996), Microsoft added support to host ActiveX controls within HTML content. If the browser encountered a page specifying an ActiveX control via an OBJECT tag, it would automatically download and install the control with little or no user intervention. This made the web "richer" but provoked objections (since such controls ran only on Windows) and security risks (especially given the lack of user intervention). Microsoft subsequently introduced security measures to make browsing including ActiveX safer.^[5]

For example:

• digital signing of installation packages (Cabinet files and executables)
• controls must explicitly declare themselves safe for scripting
• increasingly stringent default security settings
• Internet Explorer maintains a blacklist of bad controls

On 17 October 1996, Microsoft announced availability of the beta release of the Microsoft® ActiveX Software Development Kit (SDK) for the Macintosh.^[6]

Shortly thereafter, Microsoft made ActiveX open source. Documentation for ActiveX core technology resides at The Open Group and may be downloaded for free.^[7]

Other ActiveX technologies

Microsoft has developed a large number of products and software platforms using ActiveX objects. Some remain in use as of 2009:

• ActiveX Data Objects (ADO)
• Active Server Pages (ASP)
• ActiveMovie, later renamed DirectShow
• Active Messaging, later renamed Collaboration Data Objects
• Active Scripting, a technology for scripting ActiveX objects
• ActiveX Streaming Format (ASF), renamed Advanced Streaming Format, then to Advanced Systems Format

See also

• Active Setup
• Active Template Library (ATL)
• Google Native Client, an alternative development from Google
• IUnknown interface
• NPAPI, an alternative interface for web-browser plugins
• Windows DNA
• Java Beans
• Silverlight
• Flex

Notes

Note: I've tried to see this book (I had to register to open-group in order to do that), but the book doesn't exist there: 7. "Documentation for ActiveX Core Technology". The Open Group.

External links

• Activating ActiveX Controls