Note 3 for Web Scripting

Note 3 for Web Scripting

Watch & Read:

Data Type: Numerical (123..), text (string) and boolean (True - False)

A variable is a placeholder or container for use within the program. You should but you don't have to declare your variables.

var myvariable

Syntax for Variables

Variable names are case sensitive
They must begin with a letter or the underscore

The variable must not use a reserved word

abstract
as
boolean
break
byte
case
catch
char
class
continue
const
debugger
default
delete
do
double
else
enum
export
extends
false

final
finally
float
for
function
goto
if
implements
import
in
instanceof
int
interface
is
long
namespace
native
new
null
package
private

protected
public
return
short
static
super
switch
synchronized
this
throw
throws
transient
true
try
typeof
use
var
void
volatile
while
with

Global vs Local variables: When you declare a variable within a function, the variable can only be accessed within that function.

Arithmetic Operators

Operator Description Example Result

+ Addition x=4
y=2
x+y 6

- Subtraction x=5
y=3
x-y 2

* Multiplication x=5
y=6
x*y 30

/ Division 20/5
5/2 4
2.5

% Modulus (division remainder) 5%2
10%8
10%2 1
2
0

++ Increment x=8
x++ x=9

-- Decrement x=9
x-- x=8

Assignment Operators

Operator Example Is The Same As

= x=y x=y

+= x+=y x=x+y

-= x-=y x=x-y

*= x*=y x=x*y

/= x/=y x=x/y

%= x%=y x=x%y

Comparison Operators

Operator Description Example

== is equal to 6==7 returns false

===
is equal to

The difference is it checks both value and type!
x=5
y="5"
x==y returns true
x===y returns false

!= is not equal 9!=8 returns true

> is greater than 2>7 returns false

< is less than 7<9 returns true

>= is greater than or equal to 6>=7 returns false

<= is less than or equal to 1<=6 returns true

Operator	Description	Example	Result
+	Addition	x=4 y=2 x+y	6
-	Subtraction	x=5 y=3 x-y	2
*	Multiplication	x=5 y=6 x*y	30
/	Division	20/5 5/2	4 2.5
%	Modulus (division remainder)	5%2 10%8 10%2	1 2 0
++	Increment	x=8 x++	x=9
--	Decrement	x=9 x--	x=8

Operator	Example	Is The Same As
=	x=y	x=y
+=	x+=y	x=x+y
-=	x-=y	x=x-y
*=	x*=y	x=x*y
/=	x/=y	x=x/y
%=	x%=y	x=x%y

Operator	Description	Example
==	is equal to	6==7 returns false
===	is equal to The difference is it checks both value and type!	x=5 y="5" x==y returns true x===y returns false
!=	is not equal	9!=8 returns true
>	is greater than	2>7 returns false
<	is less than	7<9 returns true
>=	is greater than or equal to	6>=7 returns false
<=	is less than or equal to	1<=6 returns true

VIP:

+ is used for concatination and for addition. You have to pay attention to how the data is classified (number or string). If you need to make sure a variable is a number, use Number() methnod.

Example: X =A + B can be written as X=Number(A) + Number(B)

Terms you need to Lookup:

Variable, Array, Data types, string, boolean, global, local, reserved words

Review the following:

Variable

Homework:

Reminder: Post on the Discussion Board Section at least one URL of a Web Page that uses a Web script and describe how the script works.

You should Read Chapter 2

Final Step:

Imagine that your mind is a DVD recorder / player and you can review this content anytime you want. I want you to close your eyes and quickly review in your mind everything we covered in class.

I also want you to review everything we covered before you go to bed because I want your mind to process this information while you sleep. You don’t need to spend much time on this review, 5 minutes will be enough!