The primary use of 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. Some simple examples of this usage are:
- Opening or popping up a new window with programmatic control over the size, position and 'look' of the new window (i.e. whether the menus, toolbars, etc. are visible).
- Validation of web form input values to make sure that they will be accepted before they are submitted to the server.
- Changing images as the mouse cursor moves over them: This effect is often used to draw the user's attention to important links displayed as graphical elements.
A minimal example of a web page containing JavaScript (using
HTML 4.01 syntax) would be:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head><title>simple page</title></head>
<body>
<script type="text/javascript">
document.write('Hello World!');
</script>
<noscript>
<p>Your browser either does not support JavaScript, or you have JavaScript turned off.</p>
</noscript>
</body>
</html>
Use of java script in web pages 
