Introduction to JavaScript
JavaScript is used in millions of Web pages to improve the
design, validate forms, detect browsers, create cookies, and much more.
JavaScript is the most popular scripting language on the
internet, and works in all major browsers, such as Internet
Explorer, Firefox, and Opera.
What You Should Already Know
Before you continue you should have a basic understanding of the following:
If you want to study these subjects first, find the tutorials on our
Home
page.
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 a 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 put dynamic text into an HTML page - A JavaScript statement like this: document.write("<h1>" + name +
"</h1>") can write a variable text into an HTML page
- 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
The Real Name is ECMAScript
JavaScript's official name is "ECMAScript". The standard is
developed and maintained by the
ECMA organisation.
ECMA-262 is the official JavaScript standard. The standard is based on JavaScript (Netscape) and JScript (Microsoft).
The language was invented by Brendan
Eich at Netscape (with Navigator 2.0), and has appeared in all Netscape and Microsoft
browsers since 1996.
The development of ECMA-262 started in 1996, and the
first edition of was adopted by the ECMA General Assembly in June 1997.
The standard was approved as an international ISO (ISO/IEC
16262) standard in 1998.
The development of the standard is still in progress.
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