Javascript

Javascript

JavaScript is the name of Netscape Communications Corporation's implementation of ECMAScript, a scripting programming language based on the concept of prototypes. The language is best known for its use in websites, but is also used to enable scripting access to objects embedded in other applications.

Despite the name, JavaScript is only distantly related to the Java programming language, the main similarity being their common debt to the C programming language syntax. Semantically, JavaScript has far more in common with the Self programming language and ActionScript which is also an ECMAScript.

JavaScript is a registered trademark of Sun Microsystems, Inc., used under license for technology invented and implemented by Netscape

JavaScript was originally developed by Brendan Eich of Netscape Communications Corporation under the name Mocha, then LiveScript, and finally renamed to JavaScript. The change of name from LiveScript to JavaScript roughly coincided with Netscape adding support for Java technology in its Netscape Navigator web browser. JavaScript was first introduced and deployed in the Netscape browser version 2.0B3 in December of 1995. When web developers talk about using JavaScript in Internet Explorer, they are actually using JScript. The choice of name proved to be a source of much confusion.

As of 2006, the latest version of the language is JavaScript 1.7. The previous version 1.6 corresponded to ECMA-262 Edition 3 like JavaScript 1.5, except for Array extras, and Array and String generics. ECMAScript, in simple terms, is a standardized version of JavaScript. The ECMA-357 standard specifies E4X, a language extension dealing with XML.

JavaScript is a prototype-based scripting language with a syntax loosely based on C. Like C, the language has no input or output constructs of its own. Where C relies on standard I/O libraries, a JavaScript engine relies on a host environment into which it is embedded. There are many such host environment applications, of which web technologies are the best-known examples. These are examined first.One major use of web-based JavaScript is to write functions that are embedded in or included from HTML pages and interact with the Document Object Model (DOM) of the page to perform tasks not possible in HTML alone.

avaScript debugging has some specifics in comparison with stand-alone applications. JavaScript programs usually rely on interaction with the loaded page's Document Object Model (DOM) so errors may be caused by wrong DOM usage in a technically correct script. This makes JavaScript errors difficult to find. However nowadays both Internet Explorer and the Gecko-based browsers come with a reasonably good JavaScript debugger. Gecko browsers use the Venkman debugger or the FireBug debugger for Mozilla Firefox, while for Internet Explorer there is the Microsoft Script Debugger. Microsoft also provides Microsoft Script Editor (MSE) as part of their Microsoft Office package (Microsoft Office 2002 or higher). There are also some free online checking tools such as JSLint




FOR MORE INFORMATION ,DETAILS AND RESOURCES