Chapter 4. How JavaScript Was Created
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Chapter 4. How JavaScript Was Created

Knowing why and how JavaScript was created helps us understand why it is the way it is.

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.[4] 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:[5]

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].

By then, Netscape management had decided that a scripting language had to have a syntax similar to Java’s. That ruled out adopting existing languages such as Perl, Python, TCL, or Scheme. To defend the idea of JavaScript against competing proposals, Netscape needed a prototype. Eich wrote one in 10 days, in May 1995. JavaScript’s first code name was Mocha, coined by Marc Andreesen. Netscape marketing later changed it to LiveScript, for trademark reasons and because the names of several products already had the prefix “Live.” In late November 1995, Navigator 2.0B3 came out and included the prototype, which continued its early existence without major changes. In early December 1995, Java’s momentum had grown and the language was renamed again, to its final name, JavaScript.[6]

[4] Brendan Eich, “Popularity,” April 3, 2008,

[5] Naomi Hamilton, “The A–Z of Programming Languages: JavaScript,” Computerworld, July 30, 2008,

[6] Paul Krill, “JavaScript Creator Ponders Past, Future,” InfoWorld, June 23, 2008,; Brendan Eich, “A Brief History of JavaScript,” July 21, 2010,

Next: 5. Standardization: ECMAScript