JavaScript Introduction

What is JavaScript?

§  JavaScript was designed to add interactivity to HTML pages

§  JavaScript is a scripting language

§  A scripting language is a lightweight programming language

§  JavaScript is usually embedded directly into HTML pages

§  JavaScript is an interpreted language (means that scripts execute without preliminary compilation)

§  Everyone can use JavaScript without purchasing a license

Are Java and JavaScript the same?

NO!

Java and JavaScript are two completely different languages in both concept and design!

Java (developed by Sun Microsystems) is a powerful and much more complex programming language – in the same category as C and C++.

What Can JavaScript do?

§  JavaScript gives HTML designers a programming tool – HTML authors are normally not programmers, but JavaScript is a scripting language with a very simple syntax! Almost anyone can put small "snippets" of code into their HTML pages

§  JavaScript can react to events – A JavaScript can be set to execute when something happens, like when a page has finished loading or when a user clicks on an HTML element

§  JavaScript can read and write HTML elements – A JavaScript can read and change the content of an HTML element

§  JavaScript can be used to validate data – A JavaScript can be used to validate form data before it is submitted to a server. This saves the server from extra processing

§  JavaScript can be used to detect the visitor’s browser – A JavaScript can be used to detect the visitor’s browser, and – depending on the browser – load another page specifically designed for that browser

§  JavaScript can be used to create cookies – A JavaScript can be used to store and retrieve information on the visitor’s computer