The World Wide Web (WWW) is a hypertext-based information system that supports the use of multimedia, including text, hyperlinks, graphics, video and sound.

The nature of the World Wide Web is that communications consist of discrete and discontiguous interactions. Its like speaking once on the telephone and then hanging up as soon as a reply from the recipient is received. Normally, there is only a short time period between each interaction, although such interactions could potentially be hours or even days apart.

Until fairly recently, the World Wide Web has been used mostly as an infrastructure for document distribution. There is, however, a growing need for the ability to distribute applications in addition to static documents so as to enable users to use the information they now have access to instead of just reading it. Products such as Suns Java and Netscapes JavaScript address this issue by embedding the application inside the HTML document and having it interpreted on the client machine; this approach obviously requires that every browser on every client has the intelligence built-in in order to run such applications. This solution is unsatisfactory for a number of reasons. Firstly, an application expected to run on a variety of operating systems can make very few assumptions about the execution environment. Secondly, the code must be relatively small in size to accommodate an acceptable time for transmission over a network. Thirdly, some applications cannot assume the presence of an interpreter for their particular language, resulting in applications being written in the popular languages for which widespread browser support is known to exist. Fourthly, it cannot make assumptions about the amount of resources available (e.g. memory) on the client machine and must, therefore, keep its requirements low. The definition of client implied within this user guide is a web browser that is programmed to communicate with and ask for information from a program running on a World Wide Web server. Server, on the other hand, means a World Wide Web server that is programmed to communicate with and provide information to a client (i.e. web browser).