You will be able identify the data types available to Javascript

You will be able identify the arithmetic operators available to Javascript

Read:Chapter 2

Create:Simple Calculator and Link toHomework page!

Review:What is a Web Developer (Job requirements)

Best Practices (I don't agree with all of these)

The display difference between

document.write(variable)orgetElementById("myid").innerHTML = variable

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

## Variables:

A variable is a

placeholderorcontainerfor use within the program. You should but you don't have to declare your variables.

var myvariableSyntax for Variables

- Variable names are
case sensitive- They must begin with
a letteror theunderscore- 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

GlobalvsLocalvariables: 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+y6 - Subtraction x=5

y=3

x-y2 * Multiplication x=5

y=6

x*y30 / Division 20/5

5/24

2.5% Modulus (division remainder) 5%2

10%8

10%21

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

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)

## Arrays:

Varialbes on steroids. You can have single or multi-demansional arrays

## var arrayName = new Array();

var airplane = new Array();

airplane[0] = "747";

airplane[1] = "787";

airplane[2] = "777";or

## var arrayName = ["747", "787", "777", "737"];

var airplane= ["747", "787", "777", "737"];