Primary usage JavaScript was applied to writing of functions which are enclosed in or are switched on from HTML pages and co-operate with the Document Object model (DOM) pages.



Some simple examples of this usage:

Opening of a new window with programmed control and the control of the size, position and tags of a new window (that is, whether menus are visible, toolbars etc.).


Network ratification forms entry values to make sure, that they will be accepted before they will be presented a server.


Map change as the mouse pointer is removed them. This effect is used often to draw attention of the user to the important links shown as graphics units. As code JavaScript can run in local scale in a browser of the user (instead of on the remote server), he can respond on user's operations fast, forcing the statement to feel more sympathetic. Besides, code JavaScript can detect user's operations when one only HTML cannot, such as individual pressings the key. Statements, such as Gmail exploit it: the most part of logic of user interface is written in JavaScript and inquiries of sendings JavaScript about the information (such as the maintenance of the message of e-mail) to a server.


Engine JavaScript (also known as translator JavaScript or performance JavaScript) is the translator who interprets source text JavaScript and fulfils the original accordingly. The very first engine JavaScript has been created Brendan Eich in Corporation of Communications Netscape, for a web-browser of Navigator Netscape. The engine, under code name SpiderMonkey, is carried out in C. Since then it has been refreshed (in JavaScript 1.5) to correspond to Release ECMA-262 3. The engine of the Rhinoceros created, first of all, Norris Boyd (also in Netscape), is performance JavaScript in Java. A rhinoceros as SpiderMonkey, is Release ECMA-262 3.


The most common environment of the master for JavaScript – it is unconditional, a web-browser. Web-browsers typically use public API to create "objects of the master", responsible for reflexion DOM in JavaScript. The Network server - other common statement of the engine. JavaScript webserver would expose the objects of the master representing objects of inquiry and answer HTTP, which program JavaScript could then to control dynamically to make web pages.