Defining Variables Quiz

What is the syntax for defining a variable in JavaScript?

• var variableName;

• variableName = var

• variableName = var;

• variableName = var();

Which keyword is used to declare a variable in JavaScript?

• let

• const

• function

• var

What are the rules for naming variables in JavaScript?

• Variable names can start with a number.

• Variable names can contain spaces.

• Variable names must be at least 10 characters long.

• Variable names must start with a letter, underscore (_), or dollar sign ($).

What is the difference between var, let, and const in JavaScript?

• The difference between var, let, and const in JavaScript is that 'var' has function scope, 'let' has block scope, and 'const' is used to declare a constant variable.

• The difference between var, let, and const in JavaScript is that 'var' is used for asynchronous operations, 'let' is used for synchronous operations, and 'const' is used for callback functions.

• The difference between var, let, and const in JavaScript is that 'var' is used for global variables, 'let' is used for local variables, and 'const' is used for class variables.

• The difference between var, let, and const in JavaScript is that 'var' is used for numbers, 'let' is used for strings, and 'const' is used for booleans.

How do you assign a value to a variable in JavaScript?

• x = 10

• x = 'five'

• x = true

• x = 5

What is the scope of a variable declared with var keyword?

• block scope

• global scope

• class scope

• function scope

What is the scope of a variable declared with let keyword?

• function scope

• block scope

• global scope

• class scope

What is the scope of a variable declared with const keyword?

• global scope

• class scope

• function scope

• block scope

Can you reassign a value to a variable declared with const keyword?

• No

• Only in certain cases

• Sometimes

• Yes

What happens if you declare a variable without assigning a value to it?

• The variable will have an initial value of null.

• The variable will have an initial value of 0.

• The variable will have an initial value of false.

• The variable will have an initial value of undefined.