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JavaScript Basics Quiz

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Question 1/15

Which operator is used to assign a value to a variable?

Select your answer

===

Question 2/15

What will the following expression return: Boolean(0);

Boolean(0);

Select your answer

null

false

undefined

true

Question 3/15

When the following code is executed, what will the value of the expression be?

3 == '3'

Select your answer

true

undefined

NaN

false

Question 4/15

Which of these is not a reserved word in JavaScript?

Select your answer

switch

program

throw

default

Question 5/15

What does the "alert()" function do in JavaScript?

Select your answer

Logs a message to the console.

Displays an alert box with a message and an OK button.

Writes a message to the HTML document.

Displays an alert box with a Yes/No button.

Question 6/15

How do you find the number with the highest value of x and y?

Math.max(x, y);

Select your answer

ceil(x, y)

Math.max(x, y)

Math.ceil(x, y)

top(x, y)

Question 7/15

What is the output of the following JavaScript code?

var x = 10;
x += 5;
console.log(x);

Select your answer

Question 8/15

What method is used to add new elements to the end of an array?

Select your answer

push()

add()

append()

insert()

Question 9/15

Which one of these is an Arrow Function syntax?

Select your answer

function => (x, y){ x + y }

func (x, y) => x + y

(x, y) => x + y

function(x, y){ return x + y; }

Question 10/15

How do you call a method named "calculate" of an object named "mathObj"?

Select your answer

mathObj.calculate()

mathObj(calculate)

mathObj.calculate

mathObj:calculate()

Question 11/15

What is the output when you execute the following code?

console.log(typeof 42);

Select your answer

number

integer

object

string

Question 12/15

Which method can be used to convert a JSON string into a JavaScript object?

Select your answer

JSON.toString()

JSON.convert()

JSON.stringify()

JSON.parse()

Question 13/15

What does "const" declare in JavaScript?

Select your answer

A variable that can be changed later.

A type-checked variable.

A variable whose value is synced to the cloud.

A read-only reference to a value.

Question 14/15

What will the following code output?

var fruits = ['Apple', 'Banana', 'Mango'];
console.log(fruits[1]);

Select your answer

Mango

fruits

Banana

Apple

Question 15/15

What does "NaN" stand for in JavaScript?

Select your answer

Numerical-and-Null

Null-and-Nothing

Not-a-Number

Next-as-Number

Your Results

You did not answer any questions correctly.

Your Answers

Question 1/15

😊 Your answer was correct 🙁 Your answer was incorrect

Which operator is used to assign a value to a variable?

Available answers

===

The assignment operator in JavaScript is

, used to assign values to variables.

Question 2/15

😊 Your answer was correct 🙁 Your answer was incorrect

What will the following expression return: Boolean(0);

Boolean(0);

Available answers

null

false

undefined

true

The expression

Boolean(0)

returns

false

because

is considered a "falsy" value in JavaScript.

Question 3/15

😊 Your answer was correct 🙁 Your answer was incorrect

When the following code is executed, what will the value of the expression be?

3 == '3'

Available answers

true

undefined

NaN

false

The

==

operator checks for equality with type coercion. Hence

3 == '3'

true

Question 4/15

😊 Your answer was correct 🙁 Your answer was incorrect

Which of these is not a reserved word in JavaScript?

Available answers

switch

program

throw

default

The word

program

is not a reserved keyword in JavaScript, unlike

switch, throw, default

Question 5/15

😊 Your answer was correct 🙁 Your answer was incorrect

What does the "alert()" function do in JavaScript?

Available answers

Logs a message to the console.

Displays an alert box with a message and an OK button.

Writes a message to the HTML document.

Displays an alert box with a Yes/No button.

The

alert()

function displays an alert box containing a specified message and an OK button.

Question 6/15

😊 Your answer was correct 🙁 Your answer was incorrect

How do you find the number with the highest value of x and y?

Math.max(x, y);

Available answers

ceil(x, y)

Math.max(x, y)

Math.ceil(x, y)

top(x, y)

The function

Math.max()

is used to find the highest value among its parameters.

Question 7/15

😊 Your answer was correct 🙁 Your answer was incorrect

What is the output of the following JavaScript code?

var x = 10;
x += 5;
console.log(x);

Available answers

The code uses

+=

to add

, giving

Question 8/15

😊 Your answer was correct 🙁 Your answer was incorrect

What method is used to add new elements to the end of an array?

Available answers

push()

add()

append()

insert()

The

push()

method adds one or more elements to the end of an array.

Question 9/15

😊 Your answer was correct 🙁 Your answer was incorrect

Which one of these is an Arrow Function syntax?

Available answers

function => (x, y){ x + y }

func (x, y) => x + y

(x, y) => x + y

function(x, y){ return x + y; }

An Arrow Function does not use the

function

keyword and looks like

(x, y) => x + y

Question 10/15

😊 Your answer was correct 🙁 Your answer was incorrect

How do you call a method named "calculate" of an object named "mathObj"?

Available answers

mathObj.calculate()

mathObj(calculate)

mathObj.calculate

mathObj:calculate()

Methods of objects are called using the dot notation:

object.method()

Question 11/15

😊 Your answer was correct 🙁 Your answer was incorrect

What is the output when you execute the following code?

console.log(typeof 42);

Available answers

number

integer

object

string

The

typeof

operator returns

'number'

for numerical literals like

Question 12/15

😊 Your answer was correct 🙁 Your answer was incorrect

Which method can be used to convert a JSON string into a JavaScript object?

Available answers

JSON.toString()

JSON.convert()

JSON.stringify()

JSON.parse()

The

JSON.parse()

method is used to convert a JSON string into a JavaScript object.

Question 13/15

😊 Your answer was correct 🙁 Your answer was incorrect

What does "const" declare in JavaScript?

Available answers

A variable that can be changed later.

A type-checked variable.

A variable whose value is synced to the cloud.

A read-only reference to a value.

const

declares a variable that is read-only after initialization, meaning it cannot be reassigned.

Question 14/15

😊 Your answer was correct 🙁 Your answer was incorrect

What will the following code output?

var fruits = ['Apple', 'Banana', 'Mango'];
console.log(fruits[1]);

Available answers

Mango

fruits

Banana

Apple

Arrays in JavaScript are zero-indexed, so

fruits[1]

contains

'Banana'

Question 15/15

😊 Your answer was correct 🙁 Your answer was incorrect

What does "NaN" stand for in JavaScript?

Available answers

Numerical-and-Null

Null-and-Nothing

Not-a-Number

Next-as-Number

NaN

stands for "Not-a-Number", indicating a value that is not a legal number.