An ActiveX control is a component program object that can be re-used by many application programs within a computer or among computers in a network. The technology for creating ActiveX controls is part of Microsoft's overall ActiveX set of technologies, chief of which is the Component Object Model (COM). ActiveX controls can be downloaded as small programs or animations for Web pages, but they can also be used for any commonly-needed task by an application program in the latest Windows and Macintosh environments. In general, ActiveX controls replace the earlier OCX (Object Linking and Embedding custom controls). An ActiveX control is roughly equivalent in concept and implementation to the Java applet.
An ActiveX control can be created in any programming language that recognizes Microsoft's Component Object Model. The distributed support for COM is called the Distributed Component Object Model (DCOM). In implementation, an ActiveX control is a dynamic link library (DLL) module. An ActiveX control runs in what is known as a container, an application program that uses the Component Object Model program interfaces. This reuseable component approach to application development reduces development time and improves program capability and quality. Windows application development programs such as PowerBuilder and Microsoft Access take advantage of ActiveX controls.