Topics

Document scripts

Variables, datatypes and strings

Expressions and operators

Unit aim

To describe the basic structural elements of JavaScript, such as scripts, variables, datatypes, expressions and operators

Unit objectives

After completing this unit you should be able to

q      explain how JavaScripts can be

      incorporated in different parts of

      an HTML document

q      describe how JavaScript

      implements datatypes, variables,

      and strings

q      explain how JavaScript handles

      expressions and operators

Unit summary

When JavaScript is used to create visible content on a page, it is kept in the body of the HTML document between <SCRIPT>, </SCRIPT> tags.

When JavaScript initializes the application and prepares the browser for user input, the code is kept in the head of the document, again between <SCRIPT>, </SCRIPT> tags.

To respond to user events, JavaScript code is used for event handlers (written as HTML tag attributes) in the body of the document.