Page 144 - DCAP408_WEB_PROGRAMMING
P. 144
Web Programming
Notes false. When using numeric comparison and equality operators, the value true evaluates to 1 and
false evaluates to 0.
answer1 = true;
or
if (answer2 == false) { do something; }
5.2.2 Composite Data Types
We mentioned that there are two types of data: primitive and composite. The primitive types:
numbers, strings and Booleans—each storing a single value. Composite data types, also called
complex types, consist of more than one component. Objects, arrays, and functions, covered
later in this book, all contain a collection of components.
Objects contain properties and methods
Arrays contain a sequential list of elements
Functions contain a collection of statements
Self Assessment
Fill in the blanks:
4. ……………….. specify what kind of data, such as numbers and characters, can be stored
and manipulated within a program.
5. String literals are rows of characters enclosed in either ……………….. quotes.
6. The process of joining strings together is called ………………..
7. Composite data types, also called ……………….. types, consist of more than one component.
5.3 Variables
A variable’s purpose is to store information so that it can be used later. A variable is a symbolic
name that represents some data that you set. To think of a variable name in real world terms,
picture that the name is a grocery bag and the data it represents are the groceries. The name
wraps up the data so you can move it around a lot easier, but the name is not the data!
When using a variable for the first time it is not necessary to use “var” before the variable name,
but it is a good programming practice to make it crystal clear when a variable is being used for
the first time in the program. Here in the example VarExample.html we are showing how the
same variable can take on different values throughout a script.
Example: Illustrating variables in java script
<html>
<body>
<script type=”text/JavaScript”>
<!—
var linebreak = “<br />”
var my_var = “Hello World!”
document.write(my_var)
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