What is ActiveX?
Definition (Non-Technical):
"ActiveX™ is a set of technologies from Microsoft that enables interactive content for the World Wide Web. With ActiveX, Web sites come alive using multimedia effects, interactive objects, and sophisticated applications that create a user experience comparable to that of high-quality CD-ROM titles. ActiveX provides the glue that ties together a wide assortment of technology building blocks to enable these "active" Web sites." --Microsoft Web SiteDefinition (Technical):
"ActiveX is a component-level technology for building applications from reusable parts... ActiveX "Controls" are ActiveX objects that may provide interactive or user-controllable functions from within another program or container (such as, but not limited to a Web browser)... ActiveX controls are, like plug-ins and Java applets, small programs that can be sent over the Internet to extend the capability of your browser." --Web Developer MagazineWhat Is It Used For?
Active X can be used to enhance Web Pages with multimedia and applications. Examples would include the ability to see a movie, play a game, or view a spreadsheet or word processing document on a Web Page.
Who Can View ActiveX?
Like many Web-browser add-ons, ActiveX can only be used by NT4.0 and Windows95 users. Macintosh and UNIX support are planned for the future.
What is its relation to Java?
As far as the end-user is concerned, an ActiveX control would, like a Plug-in, JavaScript Script, or a Java Applet, appear to extend a browser to do things besides static Text and Pictures. ActiveX is faster running than Java, but is platform-dependent... unlike Java it is not "recompilable." ActiveX is less secure in nature than Java, but is more flexible and less limited. Microsoft's claim to fame with ActiveX is that it has a very small learning curve for developers who have experience with the Component Object Model (COM), while Java is a complicated C-like Programming Language. Microsoft also claims that ActiveX "provides the glue that ties together a wide assortment of technology building blocks [including Java]..."
What about security?
As mentioned above, ActiveX is less secure in nature than Java because ActiveX was designed to be very powerful while Java was designed to get the job done securely. Since ActiveX by its nature is not secure, the ActiveX proponents' main push has been to educate users on authentication of the person transmitting the ActiveX to the user's browser. This is sometimes considerably difficult over the Internet.
Notes:
Since ActiveX was created by Microsoft, the most easily compatible products, at least initially, are going to be Microsoft Products. It is unclear at this time whether "Plug-ins," "Java," or "ActiveX" are going to be the future of Web Browsers, and much of a company's decision on which to use will depend on what resources they possess or expect to possess in future years. Microsoft also has the advantage of its own browser, Microsoft Internet Explorer, which it can prepack with ActiveX controls for ease of use.
Official Microsoft ActiveX White Paper