The term ActiveX refers to a set of COM-based application programming interfaces (APIs) that were developed by Microsoft and originally released in 1996. Active X controls allow developers to embed code into their web pages and applications.
This allows for more interactive features, like live charts or streaming video, etc. ActiveX is only supported on Windows, but it can be used on any operating system if the user has access to a virtual machine such as VirtualBox.
This is a good time to point out the difference between IE plugins and ActiveX. Plugins, such as Flash Player or Java, are executed independently of the browser (they run outside of it) while ActiveX controls execute within the context of Internet Explorer (IE).
This means that if you let someone use your computer, they could potentially be able to take control of IE and do whatever they wanted. The ActiveX technology has been around since 1996; however, in recent years it has become increasingly susceptible to hacking due to security flaws in IE.
Since Microsoft’s release of Windows 8, many users have complained about not being able to use their favorite browser (such as Chrome or Firefox) anymore due to a lack of compatibility with Active X.