The Web, proper noun, is distinguished from a web, common noun, in that the Web encompasses the entire Internet. Other webs exist on private networks that may or may not be part of the Internet.
The Web grew out of a project at CERN?, beginning around 1989, where Tim Berners-Lee built the prototype system that became the core of what is now the World Wide Web. The original intent of the system was to make it easier to share research papers among colleagues.
The core functionality of the Web is based on three standards: The URL, which specifies how each page of information is given a unique "address" at which it can be found; HTTP, which specifies how the browser and server send the information to each other, and HTML, a method of encoding the information so it can be displayed on a variety of devices. Berners-Lee now heads the World Wide Web Consortium, which develops and maintains these standards and others that enable computers on the the Web to effectively store and communicate all kinds of information.
The initial "www" program at CERN only displayed text, but later browsers such as [Pei Wei]?'s Viola? (1992) added the ability to display graphics as well. [Marc Andreesen]? of NCSA? released a browser called "Mosaic? for X" in 1993 that sparked a tremendous rise in the popularity of the Web among novice users. Andreesen went on to found Mosaic Communications Corporation (now Netscape Communications). Additional features such as dynamic content, music and animation can be found in modern browsers. Frequently, the technical capability of browsers and servers advances much faster than the standards bodies can keep up, so it is not uncommon for these newer features to not work properly on all computers.
Another significant advance in the technology was Sun Microsystems Java programming language, which enabled web servers to embed small programs (called applets) directly into the information being served that would run on the user's computer, allowing faster and richer user interaction.
The similarly named, but actually quite different, JavaScript is a scripting language developed for Web pages. In conjunction with the Document Object Model, JavaScript has become a much more powerful language than its creators originally envisaged.
See also History of the Internet.