Variables Review

JavaScript Review: Variables

What is a variable?

• A container for storing a value in the computer's memory

• Once created, it can be updated repeatedly throughout the program

Use the JavaScript keyword var followed by a label and the semi-colon.

How do you create a variable?

​💡TIP: The label should describe the variable that you want to store.

• Use the label, an equal sign, and the value followed by the semi-colon.

How do you assign a value to a variable?

​💡TIP: You don't need the var keyword when assigning the value.

• The equal sign is called the "assignment operator"

Variable Naming Rules

1. Labels CAN NOT have spaces

2. Labels CAN NOT start with a number

3. Capitalization & spelling MUST match

Multiple Choice

A variable is used to:

• Store a value in memory

• Draw a circle

• Store a value that does not change

• Draw a rectangle

Multiple Choice

Which of these is NOT a good name for a variable storing your middle name?

• myMiddleName

• middleName

• x

• midNam

Multiple Select

What can be stored in a variable?

(choose 4)

• background

• color

• text

• number

• a sprite

Multiple Choice

JavaScript uses the _______ keyword to define variables.

• var

• variable

• vrb

• vari

​

When you create a variable AND assign it a value in one line of code.

​Initializing a variable

When assigning values, the equal sign

• Is not the same as math class

• In JavaScript, it sets the value

• Sometimes, you can't see the value of your variable in the program.

One Problem with variables...

• ​Use console.log(label) to show the value of the variable in the console log.

Multiple Choice

How would a computer programmer read the following line of code?

var xPosition = 500;

• The variable xPosition is equal to 500.

• The variable xPosition gets the value of 500.

Multiple Choice

How do you use a variable that has been initialized (created & given a value) in your program?

• By using a function

• By typing its name

• By opening a file

Multiple Choice

Which line of code is written correctly?

• var 2position = 25;

• var yPosition = 12

• var xPosition = 25;

• var shoe size = 10;

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