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Chapter 1:What Is JavaScript?

Chapter Description:

This chapter will describe the history of JavaScript and also what JavaScript is used for.

History of JavaScript

JavaScript started its life in 1995. It was called LiveScript at the time and it was made for Netscape Navigator 2.0. After 2 months, Netscape and Sun Microsystems turned the name into JavaScript, which is what we call it today. This caused programming chaos at that time, because many people got confused about the difference between JavaScript and Java. Microsoft's response was Internet Explorer 3.0 with something called Jscript, to avoid copyright problems. Be aware though, Java is a web application, JavaScript is a client side scripting language. For more information on the history of JavaScript, Click HERE

What is Javascript?

JavaScript is a client side scripting language that is supposed to do tasks. HTML is made just for displaying content. It does not have the power to manipulate the content or do other things to the content. JavaScript is here to do that. Before, the stuff done by the client (or viewer) would be passed to a CGI script for processing, than returned back to the HTML page. It works, but it's clumsy and slow. Think of that as normal mail. JavaScript is basically e-mail. It works faster; since it is directly implanted on the webpage rather put somewhere 5000 miles away where the CGI script is being pounded by 1000's of requests all the time. It's like giving a note to every student in a school to see, rather than posting it up on a bulletin board and having all 600 students gather together to read and memorize the contents of a 8.5 by 11 piece of paper. So, JavaScript is simply designed to do stuff. That's all there is to it.

Chapter 2:The basics of JavaScript

Chapter Description:

This chapter will describe the simple basics of JavaScript.

How to put JavaScript on a webpage?

Putting JavaScript on a webpage is very simple. There are two main ways.

Both use a script tag.

1. Use a; <script type="text/javascript">//somecode</script>

2. Include external JavaScript files; <script src="somefilename.js"/>

For this tutorial, we'll stick to the first one to avoid relative and full url as well as hosting problems.

Comments

Return

More important stuff

Basic Syntax

Comments

Comments are pieces that are in the code that do not to actually run but instead just sit there as refrences. This can be very useful if you have many many lines of code because this way you can tell where you are in the code more easily.

1.The 1'st way to do this is to put two slashes. The only problem is that this only applies to that line.
For Example:
<script type="text/javascript"> //I will not do anything I will do something </script>

2.The other way is to put a /* at the start of the comment and a */ at the end of the comment.

<script type="text/javascript">
/*I will not do anything
I will not do anything either!*/
</script>

Return

Return tells something whether to run or not. By default, it runs.

1."return true;". It continues to run.
<a href="http://google.com" onclick="return true;">I will go to google</a> Or:<a href="http://google.com">I will go to google</a>
Which will result in this:I will go to google

2."return false". It will not run.

<a href="http://google.com" onclick="return false;">I will not go to google</a>

Which will result in this:I will not go to google

More important stuff

1.JavaScript is case sensitive.
THIS:

<script type="text/javascript">
	var x=1;
</script>

Is different from
THIS:

<script type="text/javascript">
	VAR x=1;
</script>

2.You must put a semicolon(;) at the end of each JavaScript statement.
This will not work:

<script type="text/javascript">
	var x=1
	alert(x)
</script>

But this will work

<script type="text/javascript">
	var x=1;
	alert(x);
</script>

Hierarchy

This is a simple chart of JavaScript hierarchy. Not everything is included in this chart, just the ones we will be focusing on.

Chapter 3 My first JavaScript code

Write something with JavaScript

This is it! What you have been waiting for! Your first JavaScript code!

For your first code, you are going to be using something called document.write.
Open a text editor, anything will work, even something as simple as notepad if you are using a Window's computer. Just one thing, if you are running Window's, do not, I repeat, do not use WordPad.
Well, here is the code!
<html> <head> </head> <body> <script type="text/javascript"> document.write("Hello World!"); </script> </body> </html>
Save the file as an .html file, and open it in your browser.

Okay, now let's analyze the code.
1. It includes the basic html stuff(body,head...).
2. It includes the <script> tag, with the type declared as text/javascript.
3. Okay, now the command document.write. It means what it looks like, document.write, or document write
Now, after that,
("Hello World!");.
This (""); is the container for everything, doing different things depending on the command, in this case, it writes what is in it.
You could even include html tags in there! For example, you could write,
("<strong>I just wrote my first piece of JavaScript code!</strong>");
and it will display as
I just wrote my first piece of JavaScript code!!
However do not rely on this to write scads of html code, because
THIS:
document.write("<div id='example'><a class='aexample' href='www.example.com'>Example.com</a></div>");
is simply inconventional, and anyway, you have to put everything on that line, or it won't work.

Chapter 4: Changing a webpage dynamically

Chapter Description:

This chapter will describe how to change a webpage dynamically.

What does changing a webpage dynamically mean?

To change a webpage dynamically is to change its contents with something. For example, you first JavaScript code you wrote Hello World! dynamically with the document.write command.