JavaScript (redirected from JavaScript language)

JavaScript

Computer programming language developed by Netscape in 1995 for use in HTML pages. JavaScript is a scripting language (or interpreted language), which is not as fast as compiled languages (such as Java or C++) but easier to learn and use. It is only loosely related to Java, and is not a true object-oriented language (see object-oriented programming). JavaScript can be quickly added to a pure HTML page to provide dynamic features, such as automatically calculating the current date or activating an action. The JavaScript code must be interpreted and executed by a browser as it reads the Web page or by a Web server before it delivers the page to the browser.

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A popular scripting language that is widely supported in Web browsers and other Web tools. It adds interactive functions to HTML pages, which are otherwise static, since HTML is a display language, not a programming language. JavaScript is easier to use than Java, but not as powerful and deals mainly with the elements on the Web page. On the client, JavaScript is maintained as source code embedded into an HTML page. On the server, it is compiled into bytecode (intermediate language), similar to Java programs.

JavaScript evolved from Netscape's LiveScript language. First released with Navigator 2.0, it was made more compatible with Java. JavaScript does not have the programming overhead of Java, but can be used in conjunction with it. For example, a JavaScript script could be used to display a data entry form and validate the input, while a Java applet or Java servlet more thoroughly processes the information. JavaScript is also used to tie Java applets together. See JScript, Java, Java applet, servlet and VBScript.

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(language)

JavaScript - (Formerly "LiveScript") Netscape's simple, cross-platform, World-Wide Web scripting language, only very vaguely related to Java (which is a Sun trademark). JavaScript is intimately tied to the World-Wide Web, and currently runs in only three environments - as a server-side scripting language, as an embedded language in server-parsed HTML, and as an embedded language run in web browsers where it is the most important part of DHTML. JavaScript has a simplified C-like syntax and is tightly integrated with the browser Document Object Model. It is useful for implementing enhanced forms, simple web database front-ends, and navigation enhancements. It is unusual in that the scope of variables extends throughout the function in which they are declared rather than the smallest enclosing block as in C. JavaScript originated from Netscape and, for a time, only their products supported it. Microsoft now supports a work-alike which they call JScript. The resulting inconsistencies make it difficult to write JavaScript that behaves the same in all browsers. This could be attributed to the slow progress of JavaScript through the standards bodies. JavaScript runs "100x" slower than C, as it is purely interpreted (Java runs "10x" slower than C code). Netscape and allies say JavaScript is an "open standard" in an effort to keep Microsoft from monopolising web software as they have desktop software. Netscape and Sun have co-operated to enable Java and JavaScript to exchange messages and data. See also VBScript. Usenet newsgroup: news:comp.lang.javascript. Mailing List: <majordomo@obscure.org> ("subscribe javascript" in body).