Background on Executable Content

Executable content is the idea of sending around data that is actually code to be executed. Why is the idea of executable content so exciting? The answer is fairly simple. Power and expressiveness. Use of the World Wide Web has exploded over the past few years, along with this growth there have been many attempts to retrofit applications to the Web. While the Web has adapted to allow more interesting uses through forms and scripts that run on the server, these methods are extremely limiting. The ability to have users locally run a program written in a full-fledged programming language allows applications to be used directly over the Web.

Not surprisingly Java is not alone with its idea of shipping around programs to run. For example, the Safe-Tcl language (an extension of the Tcl language) attempts to provide for ``Enabled Mail'' which would allow users to send email with embedded Safe-Tcl programs. Safe-Tcl goes through great troubles to make sure that the language satisfies strong security and portability constraints. Telescript from General Magic also provides many of the same features for executable content as Java, with similar claims regarding safety and security. So why has Java received so much attention? The main reason is the Java is being supported by both Sun and Netscape. The consensus seems to be that if any language that supports executable content will make it, Java will.