What are ActiveX controls?

An activeX control is a reusable component which provide a building block that can be used by different softwares. They can be compared to java Applets in the sense that both of them act as an abstraction layer between the developer and the operating system. But the differences lie in the facts that while java applets can run in any platform, ActiveX components are compatible only with microsoft OS and browser. Due to the higher command of ActiveX over windows, they are sometimes very dangerous. As a result, malwares and other computer viruses finds it an easy way to attack a system, distributing themselves through the net as ActiveX applets.