It used to make web pages interactive.
In 1993, NCSA’s Mosaic was the first widely popular web browser. In 1994, a company called Netscape was founded to exploit the potential of the nascent World Wide Web. Netscape created the proprietary web browser Netscape Navigator, which was dominant throughout the 1990s. Many of the original Mosaic authors went on to work on Navigator, but the two intentionally shared no code.
Netscape quickly realized that the Web needed to become more dynamic. Even if you simply wanted to check that users entered correct values in a form, you needed to send the data to the server in order to give feedback. In 1995, Netscape hired Brendan Eich with the promise of letting him implement Scheme (a Lisp dialect) in the browser. Before he could get started, Netscape collaborated with hardware and software company Sun (since bought by Oracle) to include its more static programming language, Java, in Navigator. As a consequence, a hotly debated question at Netscape was why the Web needed two programming languages: Java and a scripting language. The proponents of a scripting language offered the following explanation:
We aimed to provide a “glue language” for the Web designers and part time programmers who were building Web content from components such as images, plugins, and Java applets. We saw Java as the “component language” used by higher-priced programmers, where the glue programmers — the Web page designers — would assemble components and automate their interactions using [a scripting language].
- Brendan Eich, “Popularity,” April 3, 2008,