JAVASCRIPT
JavaScript is the programming language of HTML and the
Web. Programming makes computers do what you want them to do. JavaScript is easy to learn.
JavaScript is a lightweight, interpreted
programming language. It is designed for creating network-centric applications.
It is complimentary to and integrated with Java. JavaScript is very easy to
implement because it is integrated with HTML. It is open and cross-platform.
Example:
<html>
<body>
<script language="javascript" type="text/javascript">
<!--
document.write("Hello World!")
//-->
</script>
</body>
</html>
What is JavaScript ?
Javascript
is a dynamic computer programming language. It is lightweight and most commonly
used as a part of web pages, whose implementations allow client-side script to
interact with the user and make dynamic pages. It is an interpreted programming
language with object-oriented capabilities.
JavaScript
was first known as LiveScript, but Netscape changed its name
to JavaScript, possibly because of the excitement being generated by Java.
JavaScript made its first appearance in Netscape 2.0 in 1995 with the nameLiveScript.
The general-purpose core of the language has been embedded in Netscape,
Internet Explorer, and other web browsers.
The ECMA-262
Specification defined a standard version of the core JavaScript
language.
·
JavaScript is a lightweight, interpreted
programming language.
·
Designed for creating network-centric
applications.
·
Complementary to and integrated with Java.
·
Complementary to and integrated with HTML.
·
Open and cross-platform
Client-side JavaScript
Client-side
JavaScript is the most common form of the language. The script should be
included in or referenced by an HTML document for the code to be interpreted by
the browser.
It
means that a web page need not be a static HTML, but can include programs that
interact with the user, control the browser, and dynamically create HTML
content.
The
JavaScript client-side mechanism provides many advantages over traditional CGI
server-side scripts. For example, you might use JavaScript to check if the user
has entered a valid e-mail address in a form field.
The
JavaScript code is executed when the user submits the form, and only if all the
entries are valid, they would be submitted to the Web Server.
JavaScript
can be used to trap user-initiated events such as button clicks, link
navigation, and other actions that the user initiates explicitly or implicitly.
Advantages of JavaScript
The
merits of using JavaScript are −
·
Less server
interaction − You can validate user input before sending the page off
to the server. This saves server traffic, which means less load on your server.
·
Immediate feedback to
the visitors − They don't have to wait for a page reload to see if
they have forgotten to enter something.
·
Increased
interactivity − You can create interfaces that react when the user
hovers over them with a mouse or activates them via the keyboard.
·
Richer interfaces − You can
use JavaScript to include such items as drag-and-drop components and sliders to
give a Rich Interface to your site visitors.
Limitations of JavaScript
We
cannot treat JavaScript as a full-fledged programming language. It lacks the
following important features −
·
Client-side JavaScript does not allow the
reading or writing of files. This has been kept for security reason.
·
JavaScript cannot be used for networking
applications because there is no such support available.
·
JavaScript doesn't have any multithreading or
multiprocessor capabilities.
Once
again, JavaScript is a lightweight, interpreted programming language that
allows you to build interactivity into otherwise static HTML pages.
JavaScript Development Tools
One
of major strengths of JavaScript is that it does not require expensive development
tools. You can start with a simple text editor such as Notepad. Since it is an
interpreted language inside the context of a web browser, you don't even need
to buy a compiler.
To
make our life simpler, various vendors have come up with very nice JavaScript
editing tools. Some of them are listed here −
·
Microsoft FrontPage −
Microsoft has developed a popular HTML editor called FrontPage. FrontPage also
provides web developers with a number of JavaScript tools to assist in the
creation of interactive websites.
·
Macromedia Dreamweaver
MX − Macromedia Dreamweaver MX is a very popular HTML and
JavaScript editor in the professional web development crowd. It provides
several handy prebuilt JavaScript components, integrates well with databases,
and conforms to new standards such as XHTML and XML.
·
Macromedia HomeSite 5 − HomeSite
5 is a well-liked HTML and JavaScript editor from Macromedia that can be used
to manage personal websites effectively.
No comments:
Post a Comment