Multimedia Glossary: J

Java

Java is an object-oriented programming language released by Sun in 1992. Java is similar to C++ but was introduced due to some problems experienced with C++ such as memory leaks and multiple inheritance. Java is both compiled and interpreted, and architecture neutral. It can thus run on a very wide range of devices with minimum effort. Java is further portable and multithreaded (many things can happen simultaneously).

JavaScript

JavaScript is a scripting language originally developed by Netscape in 1995 for Netscape 2.0. It was originally called LiveScript, but renamed JavaScript as it was viewed to be complementing Java. JavaScript is an interpreted scripting language that is typically executed by the browser (i.e. on the client-side). However, there is also server-side JavaScript which is executed on the server. JavaScript 1. 0 has become a standard, known as ECMAScript.

Joint Photographic Experts Group

See JPEG

JPEG / JPG

Joint Photographic Experts Group

Pronounced jay-peg.

JPEG is a bitmap compression format for images. The proper abbreviation is JPEG, but DOS-based computers could only take a 3-character extension, so you will often see the shortened version: JPG. JPEG is based on a 24-bit color palette, but it is lossy, which means that it drops information that is compressed out. Compression ratios may range from 10:1 to 20:1 and most graphic application programs (such as Adobe Photoshop) allow you to choose the compression rate. Obviously, the more compressed, the more data is lost, but the less compressed the larger the files size of the image. It takes considerable experience and skill to play around with different modes and pallettes as well as compression ratios to get a good quality result with a relatively small JPEG file size. JPEG is typically used for complex images and photographs. It supports 16.7 million colors.

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JScript

JScript is Microsoft's version of JavaScript, based on the published documents of Netscape. However, Netscape did not publish all the features, so Microsoft developed their own stuff, which led to discrepancies as these different versions clashed. Fortunately Microsoft has dropped JScript altogether, but, unfortunately they are still pushing their own platform-specific products to the Web, whose purpose is to be platform independent.

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