Computerworld is undertaking a series of investigations into the most widely-used programming languages. Previously we have spoken to Alfred v. Aho of AWK fame, S. Tucker Taft on the Ada 1995 and 2005 revisions, Microsoft about its server-side script engine ASP, Chet Ramey about his experience maintaining Bash, Bjarne Stroustrup of C++ fame, to Charles H. Moore about the design and development of Forth, a chat with the irreverent Don Woods about the development and uses of INTERCAL, Stephen C. Johnson on YACC, Modula-3 design committee member, Luca Cardelli and Walter Bright about D
Please note that we are no longer following exact alphabetical order for this series, due to popular demand. If you'd like to submit any suggestions for programming languages or language authors that you'd like to see covered, please email firstname.lastname@example.org.
I've written about the early history on my blog: http://Weblogs.mozillazine.org/roadmap/archives/2008/04/popularity.html
The impetus was the belief on the part of at least Marc Andreessen and myself, along with Bill Joy of Sun, that HTML needed a "scripting language", a programming language that was easy to use by amateurs and novices, where the code could be written directly in source form as part of the Web page markup. 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 JS.
In this sense, JS was analogous to Visual Basic, and Java to C++, in Microsoft's programming language family used on Windows and in its applications. This division of labor across the programming pyramid fosters greater innovation than alternatives that require all programmers to use the "real" programming language (Java or C++) instead of the "little" scripting language.
So was there a particular problem you were trying to solve?
The lack of programmability of Web pages made them static, text-heavy, with at best images in tables or floating on the right or left. With a scripting language like JS that could touch elements of the page, change their properties, and respond to events, we envisioned a much livelier Web consisting of pages that acted more like applications.
Indeed, some early adopters, even in late 1995 (Netscape 2's beta period), built advanced Web apps using JS and frames in framesets, prefiguring the "Ajax" or "Web 2.0" style of development. But machines were slower then, JS had a relatively impoverished initial set of browser APIs, and the means to communicate with servers generally involved reloading whole Web pages.
See my blog post, linked above.
Why was JS originally named Mocha and then LiveScript?
Mocha was Marc Andreessen's code name, but Netscape marketing saw potential trademark conflicts and did not prefer it on other grounds. They had a "live" meme going in their naming (LiveWire, LiveScript, etc.). But the Java momentum of the time (1995-1996) swept these before it.