ActiveX controls are small programs, also known as add-ons, that are used on the Internet to provide interactive content for web pages. They are based on Microsoft's Component Object Model (COM) technology and are primarily used in the Windows operating system. ActiveX controls can perform a wide range of tasks, such as displaying animations, playing audio and video, providing interactive forms, and accessing system resources. They are often embedded within web pages and executed by web browsers like Internet Explorer (though support has largely been deprecated in modern browsers due to security concerns). Because ActiveX controls have access to the underlying operating system, they can pose a security risk if they are not properly designed or if they come from untrusted sources. Malicious ActiveX controls can be used to install malware, steal data, or compromise the security of the user's system. Modern web development practices favor alternatives like JavaScript and HTML5 due to their cross-platform compatibility and improved security features.