ActiveX is a software technology created by Microsoft for use in developing interactive and dynamic web applications. It allows developers to embed small programs, known as "controls," into web pages, enabling users to interact with web content in a more engaging and interactive way. ActiveX controls are often used for multimedia content, such as videos and animations, as well as for complex web applications that require advanced functionality. However, ActiveX controls are typically only compatible with Internet Explorer, which limits their widespread use in today's multi-browser environment.