ActiveX

ActiveX is a framework for defining reusable software components in a programming language-independent way. Software applications can then be composed from one or more of these components in order to provide their functionality.^[1]

It was introduced in 1996 by Microsoft as a development of its Component Object Model (COM) and Object Linking and Embedding (OLE) technologies and is commonly used in its Windows operating system, although the technology itself is not tied to it.

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 embedding ActiveX controls onto web pages.

ActiveX controls

ActiveX controls, mini program building blocks, can serve to create distributed applications working over the Internet through web browsers. Examples include customized applications for gathering data, viewing certain kinds of files, and displaying animation.

ActiveX controls are comparable to Java applets: programmers designed both of these mechanisms to allow web browsers to download and execute them. But Java applets can run on nearly any platform, while ActiveX components officially operate only with Microsoft's Internet Explorer web browser and the Microsoft Windows operating system.^[2]

Malwares, e.g. computer viruses and spywares, can be accidentally installed from malicious websites using ActiveX controls (drive-by downloads).

Programmers can write ActiveX controls in any language which supports COM component development, including the following languages/environments:

• C++ either directly or with the help of libraries such as ATL or MFC^[3]
• Borland Delphi
• Visual Basic
• .NET Framework (C#/VB.NET)

Common examples of ActiveX controls include command buttons, list boxes, dialog boxes, and the Internet Explorer browser.^{[citation needed]}

History

Faced with the complexity of OLE 2.0 and with poor support for COM in MFC, Microsoft rationalized the specifications to make them simpler, and rebranded the technology as ActiveX in 1996.^[4][5] 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^[6] . 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

ActiveX in non-IE applications

It may not always be possible to use Internet Explorer to execute ActiveX content (e.g. on a Wine installation), nor may a user want to.

• FF ActiveX Host can run ActiveX controls in Mozilla Firefox for Windows.
• Mozilla ActiveX Control was last updated in late 2005, and runs in Firefox 1.5.
• MediaWrap for Firefox was last updated on 12 June 2008, and will run in Firefox 1.5 to 3.5.*.

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

1. ^ Introduction to ActiveX Controls at microsoft.com, accessed 18 January 2008
2. ^ "ActiveX". 2009-02-24. http://support.mozilla.com/en-US/kb/Activex. Retrieved 2009-03-12. "As a Microsoft product, Active X was specifically designed to work with Windows systems. ActiveX is not supported by Microsoft on other operating systems e.g. Mac OS X or GNU/Linux." 
3. ^ http://msdn.microsoft.com/en-us/library/ms974283.aspx Creating ActiveX Components in C++
4. ^ "Using ActiveX with LabVIEW – Examining Mission Editor Version 1.0". NI Developer Zone. National Instruments. 2007-08-13. http://zone.ni.com/devzone/cda/tut/p/id/4496. Retrieved 2009-03-12. "The term ActiveX surfaced in the Microsoft world in early 1996." 
5. ^ "Microsoft Announces ActiveX Technologies: Microsoft Corp. announced ActiveX Technologies, which make it easy for the broadest range of software developers and Web designers to build dynamic content for the Internet and the PC.". Microsoft PressPass. Microsoft. 1996-03-12. http://www.microsoft.com/presspass/press/1996/mar96/activxpr.mspx. Retrieved 2009-03-12. "San Francisco, March 12, 1996 - Microsoft Corporation. today announced ActiveX ... Technologies, which make it easy for the broadest range of software developers and Web designers to build dynamic content for the Internet and the PC. ... ActiveX Technologies form a robust framework for creating interactive content using software components, scripts and existing applications. Specifically, ActiveX Technologies enable developers to build Web content easily using ActiveX Controls (formerly OLE Controls), active scripts and active documents. ... ActiveX Technologies are available in the form of the Microsoft ActiveX Development Kit, which is being distributed to more than 4,000 developers attending the Professional Developers Conference in San Francisco todaynot true." 
6. ^ "Activating ActiveX Controls". Activating ActiveX Controls. 1900-1-0. http://capitalhead.com/articles/activating-activex-controls.aspx. Retrieved 2009-06-16. 

External links

• Source to simple ActiveX control
• Activating ActiveX Controls