Javascript
This JavaScript Tutorial is for beginners. It teaches you JavaScript from the ground up - starting with the basics.
This tutorial assumes you are comfortable coding HTML. If you aren't comfortable with HTML, start with the HTML Tutorial first, then return to this page to learn JavaScript!
JavaScript is THE scripting language of the Web.
JavaScript is used in billions of Web pages to add functionality, validate forms, communicate with the server, and much more.
JavaScript is easy to learn. You will enjoy it.
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
JavaScript = ECMAScript
JavaScript is an implementation of the ECMAScript language standard. ECMA-262 is the official JavaScript standard.
JavaScript was invented by Brendan Eich at Netscape (with Navigator 2.0), and has appeared in all browsers since 1996.
The official standardization was adopted by the ECMA organization (an industry standardization association) in 1997.
The ECMA standard (called ECMAScript-262) was approved as an international ISO (ISO/IEC 16262) standard in 1998.
The development is still in progress.
To view webpages with JavaScript, you need to ensure your browser has JavaScript enabled. Generally speaking, you can still view the webpage without JavaScript, but you will not be able to take advantage of the JavaScript functionality.
How do I check if my browser has JavaScript enabled?
You normally do this by checking your browser's options. This will depend on the browser you're using. Instructions for some of the more common browsers are below:
Internet Explorer (6.0):
1. Go to Tools from the top menu
2. Select Internet Options
3. Click on the Security tab
4. Click Custom Level
5. Scroll down until you see the Scripting section
6. Ensure that the Active Scripting option is set at Enabled
7. Click OK
Netscape Navigator (4.8):
1. Go to Edit from the top menu
2. Select Preferences
3. Select Advanced
4. Select Scripts & Plugins
5. Check the Enable JavaScript checkbox
6. Click OK
Mozilla Firefox (1.0):
1. Go to Tools from the top menu
2. Select Options
3. Select Web Features from the left menu
4. Ensure the Enable JavaScript option is checked
5. Click OK
Mozilla Firefox (1.5):
1. Go to Tools from the top menu
2. Select Options
3. Click on the Content button
4. Ensure that the Enable JavaScript option is checked
5. Click OK
Apple Safari (1.0):
1. Go to Safari from the top menu
2. Select Preferences
3. Select Security
4. Ensure that the Enable JavaScript option is checked
5. Click OK
How do I disable JavaScript?
You simply go through the steps above but ensure the JavaScript options are not checked/selected.
If you're developing web pages with JavaScript, it's good practice to view your website with JavaScript disabled. This will show you what your website will look like to users who choose to disable JavaScript.
Other browsers?
Most (if not all browsers) give you the option to enable/disable JavaScript. If your browser is not listed above, the steps above will give you some idea of how to find it. Just look for something called tools, options, preferences or something similar.
