Target Audience:
Novice web programmers, Computer science students.
Content:
This article attempts to clarify in simple terms: what is javascript and how to get started with it.
Author: Mahesh Jagadesan,
Mahesh is a Technical Consultant in Tech Mahindra, India.
He is an experienced Javascript programmer.
What is JavaScript?
It’s a scripting language that’s most commonly used for enhancing the functionality and look of websites. Of late, it’s become one of the most-used languages ever since the concept of Web 2.0 has caught on.
Show me JavaScript in action
Go to http://mail.google.com
Are Java and JavaScript the same?
No, not at all. Java is an object-oriented programming language; Javascript is an object-based programming language. Programs written in either language can be run irrespective of the OS. Java needs a JVM; Javascript needs an interpreter. Most web browsers have a Javascript interpreter built into them, so you should usually be able to test your Javascript code without having to install any software, not even a JVM. See this article for more on JAVA.
Do I need to know java for learning JavaScript?
No.
Now what is Ajax?
AJAX, as it should be called, is a combination of different technologies. It is used nowadays to provide a desktop-like feel to web applications. It consists of JavaScript, asynchronous requests and responses, and XML (for transferring data). It does NOT refer to simple JavaScript function calls; instead, a web application can be said to use AJAX only if it uses asynchronous HTTP calls to a web server.
In other words: AJAX is that part of JavaScript which is used to perform operations behind the scenes without user getting to know about it. Typically, the whole page doesn’t get refreshed, only some portions of it.
What is HTML?
It’s a mark-up language that’s the mainstay of the Internet. It is used to present information in a visually appealing manner. It enables hyper-linking, that is, inter-linking of web pages.
What is XML?
Born in the same family of mark-up languages as HTML, it’s a very capable medium for data transfer. Data in an XML document is hierarchical in nature, and can hence be parsed by software, which is why it’s wildly popular.
What is CSS?
CSS is to HTML what colours and nice frames are to a simple sketch. Before CSS, the HTML in web pages catered to both the content, and its presentation. CSS is the result of an attempt to separate content from presentation, and it has resulted in adding a few frills to web pages as well.
How are HTML, XML and CSS connected with JavaScript?
JavaScript can modify, programmatically, the HTML and CSS that comprise a web page, thus creating a very dynamic interface to the Web. This is made possible by the implementation of the Document Object Model (DOM). The same DOM concept is also responsible for JavaScript being able to parse XML.In other words, DOM brings together HTML and CSS, also enabling programmatic parsing of XML.
What software should I download for JavaScript?
JavaScript is usually embedded within web pages, and can be run on most browsers (Opera, IE, and Firefox), so you don’t really need any special software for it. All you need is a text editor (even Notepad would do) and a web browser.
What all can I do with JavaScript?
You can do quite a lot with JavaScript, including a web application that’s as rich as a thick desktop client – you’re limited only by your imagination!
What is the starting point to learn JavaScript/ where can I learn it?
The starting point would be any good JavaScript book that starts with the basics. Or you could always read online – starting from http://www.quirksmode.org/js/contents.html or http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Guide
What are the prospects of JavaScript or why should i learn .
Web 2.0 and AJAX are hot topics now. Plus, web browsers have become more mature, with the result that JavaScript is more and more of a standard requirement. This is evidenced by the number of JavaScript libraries that are available out there. Though not sufficient in itself, a good knowledge of JavaScript combined with sound fundamentals and one or more programming languages will stand you in good stead in IT.
Author can be reached at maheshj(at)gmx(dot)net in case of queries. Feedback is welcome.
Related Posts:
Learn what is JAVA
About the Author: Written by Mahesh Jagadeesan. Mahesh is an experienced IT professional with 10+ years of experience. If you need a hand with anything related to Perl, Javascript, HTML or any computer problem, drop him a line (maheshj at gmx dot net) or through his website at The Practical Idealist 
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