read04a.md

JavaScript

The JavaScript is added last and enhances the usability of the page or the experience of interacting with the site.

It's written in plain text, just like HTML and CSS, so you do not need any new tools to write a script.

How to write script of web pages :

• It is best to keep JavaScript code in its own JavaScript file. JavaScript files are text files (like HTML pages and CSS style sheets), but they have the . j s extension.

• The HTML <script> element is used in HTML pages to tell the browser to load the JavaScript file (rather like the element can be used to load a CSS file).

• If you view the source code of the page in the browser, the JavaScript will not have changed the HTML, because the script works with the model of the web page that the browser has created.

So , What does the Script mean?

A script is a series of instructions that a computer can follow one-by-one.

Each individual instruction or step is known as a statement. Statements should end with a semicolon

Variables

A script will have to temporarily store the bits of information it needs to do its job. It can store this data in variables.

There are too many types of variables ; We explain them in the table below .

Variable	Code Type	Data Type
Integer	int	number
Float	float	number
Double	double	number
String	string	text
Charachter	char	text
Boolian	bool	structure type that represents a Boolean value, which can be either true or false.

Finally the image below show the main differences between JavaScript , HTML and CSS languages

References

** JAVASCRIPT & JQUERY Interactive Front-End Web Development Book ** , which was written by *** JON DUCKETT ***