Wednesday, March 12, 2008

Javascript and it Characteristics

What is JavaScript?

JavaScript Is a Scripting Language :-
Scripting languages used for interactivity to Web pages. JavaScript is an object-based scripting language. JavaScript is interpreted, which provides an easy development process; it contains a limited and easy-to-learn command set and syntax; and it is designed for performing a well-defined set of tasks.
Designed for Simple, Small Programs
Because JavaScript is a scripting language, it is well-suited to implementing simple, small programs. Tasks can be easily written and performed at acceptable speeds with JavaScript and would be easily integrated into a Web page. In java script quick development and easy maintenance of every types of applications.
Of course, this doesn't mean that sophisticated applications can't be—and aren't being— developed with JavaScript. Nonetheless, scripting languages are generally used for smaller tasks rather than full, compiled programs.
Performs Repetitive Tasks
JavaScript is suited to producing small programs; it is especially well-designed for repetitive, event-invoked tasks. For example, JavaScript is ideal for calculating the content of one field in a form based on changes to the data in another field. Each time the data changes, the JavaScript program to handle the event is invoked, and the new data for the other field is calculated and displayed.
Designed for Programming User Events
Because of the way in which JavaScript is integrated into the browser and can interact directly with HTML pages, JavaScript makes it possible to program responses to user events such as mouse clicks and data entry in forms.
For instance, a JavaScript script could be used to implement a simple help system. Whenever the user points at a button or a link on the page, a helpful and informative message can be displayed in the status bar at the bottom of the browser window. This adds interactivity to Web pages makes forms dynamic and can decrease the bandwidth requirements and server load incurred by using forms and CGI programming.
Easy Debugging and Testing
Like other scripting languages, JavaScript eases development and trouble-shooting because it is not compiled. It is easy to test program code, look at the results, make changes and test it again without the overhead and delay of compiling.

Not Fully Extensible
JavaScript is not fully extensible. The JavaScript model is one of a limited set of base objects, properties, methods, and data types, which provide enough capabilities to create client-side applications. Users can create their own objects and write functions but not purely object oriented its object based scripting language.
Limited client-server interaction
JavaScript in its current form is not designed for complete client-server interaction. JavaScript is well-suited to handling client-end activity.
JavaScript will be part of the Live-Wire Web server being developed by Netscape. Live-Wire is aimed at groups and organizations developing interactive Web applications. In this role, JavaScript will provide an alternative to today's CGI scripting for server-end programming.
Integrated into HTML
JavaScript is tightly integrated into HTML files. Typically, entire scripts are in the same files as the HTML that defines a page and are downloaded at the same time as the HTML files.

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