JavaScript Programming Quizzes for Year 10 Computing Students

Question 1

In JavaScript, what is the primary purpose of the 'this' keyword?

Accepted Answer

To refer to the object that owns the code block currently being executed

Answer

To refer to the function currently being executed

Answer

To refer to the global object of the program

Answer

To refer to the parent object of the object associated with the code block being executed

Question 2

Explain the difference between a variable and a constant in JavaScript.

Accepted Answer

Variables can be reassigned, but constants cannot

Answer

Constants can be reassigned, but variables cannot

Answer

They are essentially the same concept

Answer

Variables are stored in memory, while constants are stored on disk

Question 3

What is the difference between the '==' and '===' equality operators in JavaScript?

Accepted Answer

The '==' operator compares only values, while the '===' operator compares both values and data types.

Answer

The '===' operator compares only values, while the '==' operator compares both values and data types.

Answer

There is no difference between '==' and '==='.

Answer

Both operators compare values and data types.

Question 4

When a user clicks on an HTML element, which event occurs?

Accepted Answer

click

Answer

load

Answer

change

Answer

mouseenter

Question 5

What is the main purpose of the 'this' keyword in JavaScript?

Accepted Answer

To refer to the current object.

Answer

To refer to the global object.

Answer

To call a method on the current object.

Answer

To create a new object.

Question 6

Which JavaScript method would you use to add a new element to an array?

Accepted Answer

push

Answer

add

Answer

insert

Answer

append

Question 7

What is the primary purpose of the `var` keyword in JavaScript?

Accepted Answer

To declare a variable

Answer

To define a function

Answer

To create an object

Answer

To loop through an array

Question 8

Select the correct syntax for defining a function in JavaScript:

Accepted Answer

function myFunction(params) {}

Answer

myFunction(params) -> {}

Answer

{myFunction(params)}

Answer

define myFunction(params) {}

Question 9

What distinguishes between an `alert()` and a `console.log()` statement in JavaScript?

Accepted Answer

`alert()` displays a pop-up message and halts execution, while `console.log()` only outputs information to the console.

Answer

`console.log()` displays a pop-up message and halts execution, while `alert()` only outputs information to the console.

Answer

Both `alert()` and `console.log()` display pop-up messages.

Answer

Both `alert()` and `console.log()` output information to the console.

Question 10

Which event listener is used to detect when a button is clicked?

Accepted Answer

onclick

Answer

onmouseover

Answer

onload

Answer

onsubmit

Question 11

What is the purpose of the `getElementById()` method in JavaScript?

Accepted Answer

To retrieve the element with the specified ID from the HTML document

Answer

To create a new element in the HTML document

Answer

To remove an element from the HTML document

Answer

To modify the style of an element in the HTML document

Question 12

Which of the following is NOT a valid JavaScript data type?

Accepted Answer

Function

Answer

Number

Answer

String

Answer

Boolean

Question 13

What is the purpose of the 'let' keyword in JavaScript?

Accepted Answer

To declare a variable with block scope

Answer

To declare a constant

Answer

To declare a function

Answer

To declare an object

Question 14

What is the purpose of using a JavaScript debugger?

Accepted Answer

To identify and fix errors in JavaScript code

Answer

To speed up the execution of JavaScript code

Answer

To create new JavaScript objects

Answer

To store data securely

Question 15

What is the primary purpose of the 'return' statement in a JavaScript function?

Accepted Answer

To end the function and provide an optional result.

Answer

To invoke another function within the current function.

Answer

To define a variable accessible within the function.

Answer

To manage user input.

Question 16

Which event listener is used to detect mouse clicks in JavaScript?

Accepted Answer

onclick

Answer

onmouseover

Answer

onfocus

Answer

onload

Question 17

What is the key difference between 'let' and 'const' variables in JavaScript?

Accepted Answer

'let' allows reassignment, while 'const' does not.

Answer

'const' allows reassignment, while 'let' does not.

Answer

They have no difference in behavior.

Answer

They serve different purposes in JavaScript.

Question 18

Which option is NOT a primitive data type in JavaScript?

Accepted Answer

Object

Answer

String

Answer

Number

Answer

Boolean

Question 19

What is the primary reason for using 'strict mode' in JavaScript?

Accepted Answer

To enforce best practices and prevent common errors.

Answer

To enhance the execution speed of JavaScript code.

Answer

To access new and experimental JavaScript features.

Answer

To establish a dedicated debugging environment.

Question 20

Which of the following is used to define a variable with a limited scope in JavaScript?

Accepted Answer

let

Answer

var

Answer

const

Answer

function

Question 21

Which event listener is used to detect a user clicking on an HTML element?

Accepted Answer

onclick

Answer

onmouseover

Answer

onfocus

Answer

onload

Question 22

Which among the options is NOT an inherent object in JavaScript?

Accepted Answer

MyObject

Answer

Array

Answer

Date

Answer

Math

Question 23

What is the purpose of the 'let' keyword in JavaScript?

Accepted Answer

To declare a variable with block scope

Answer

To define a function

Answer

To create an object

Answer

To handle events

Question 24

Which event listener is used to detect when a mouse button is clicked?

Accepted Answer

onclick

Answer

onmouseover

Answer

onload

Answer

onsubmit

Question 25

What is the purpose of the 'document.querySelector()' method in JavaScript?

Accepted Answer

To get the first element that matches a specified CSS selector

Answer

To create a new element

Answer

To add an event listener

Answer

To remove an element

Question 26

What is the purpose of the 'console.log()' method in JavaScript?

Accepted Answer

To print information to the console

Answer

To create a new variable

Answer

To add an event listener

Answer

To redirect the page

Question 27

Which statement is used to listen for an event and execute code when it occurs?

Accepted Answer

addEventListener(, )

Answer

attachEvent(, )

Answer

bindEvent(, )

Answer

triggerEvent(<event-type>)

Question 28

What is the primary purpose of the 'this' keyword in JavaScript?

Accepted Answer

To refer to the current object containing the code that is being executed

Answer

To access global variables

Answer

To create new objects

Answer

To define functions

Question 29

What is the difference between a for loop and a while loop in JavaScript?

Accepted Answer

For loops are used for iterating over a specific number of times, while while loops are used for iterating as long as a condition is met

Answer

While loops are used for iterating over a specific number of times, while for loops are used for iterating as long as a condition is met

Answer

There is no difference between for loops and while loops

Answer

Both of the above

Question 30

What is the correct syntax to declare a function in JavaScript?

Accepted Answer

function myFunction(params) {}

Answer

func myFunction(params) {}

Answer

myFunction(params) = function {}

Answer

declare function myFunction(params) {}

Question 31

Which of the following is NOT a primitive data type in JavaScript?

Accepted Answer

Object

Answer

String

Answer

Number

Answer

Boolean

Question 32

What is the primary purpose of using the 'this' keyword in JavaScript?

Accepted Answer

To refer to the current object

Answer

To assign a value to the current object

Answer

To create a new object

Answer

To access properties of the global object

Question 33

Which event handler in JavaScript is primarily used to detect when a user interacts with an HTML element by clicking on it?

Accepted Answer

onclick

Answer

onhover

Answer

onfocus

Answer

onchange

Question 34

What is the difference between the usage and behavior of 'let' and 'const' variables in JavaScript?

Accepted Answer

Let variables can be reassigned, while const variables cannot.

Answer

Const variables can be reassigned, while let variables cannot.

Answer

Both let and const variables can be reassigned without any restrictions.

Answer

Neither let nor const variables can be reassigned.

Question 35

Which of the following is an array method in JavaScript that is used to iterate over each element in an array?

Accepted Answer

forEach

Answer

map

Answer

filter

Answer

reduce

Question 36

What is the primary purpose of a try-catch block in JavaScript?

Accepted Answer

To handle errors and exceptions gracefully.

Answer

To prevent errors and exceptions from being thrown.

Answer

To create custom error messages and display them to the user.

Answer

To control the flow of a program by executing specific code blocks only when certain conditions are met.

Question 37

Which of the following is a valid regular expression in JavaScript for matching a string containing only uppercase and lowercase letters?

Accepted Answer

/^[a-zA-Z]+$/

Answer

[a-zA-Z]+

Answer

^a-zA-Z$

Answer

a-zA-Z+

Question 38

What does the term 'DOM' refer to in JavaScript?

Accepted Answer

Document Object Model

Answer

Document Object Manager

Answer

Data Object Model

Answer

Data Object Manager

Question 39

What is the primary purpose of the 'getElementById' method in JavaScript?

Accepted Answer

To select an HTML element by its ID

Answer

To create a new HTML element

Answer

To add an event listener to an element

Answer

To manipulate the CSS of an element

Question 40

In JavaScript, which of the following is the correct syntax to declare a variable named 'age' and assign it a value of 25?

Accepted Answer

var age = 25

Answer

int age = 25

Answer

long age = 25

Answer

byte age = 25

Question 41

What is the purpose of the 'this' keyword in JavaScript?

Accepted Answer

To refer to the current object

Answer

To refer to the global object

Answer

To refer to the parent object

Answer

To refer to the child object

Question 42

Which event listener is used to execute code when an HTML element is clicked?

Accepted Answer

onclick

Answer

onchange

Answer

onload

Answer

onmouseover

Question 43

What is the result of the following JavaScript code: let num = 10; num++;?

Accepted Answer

11

Answer

10

Answer

NaN

Answer

undefined

Question 44

Which of the following is NOT a primitive data type in JavaScript?

Accepted Answer

Object

Answer

String

Answer

Integer

Answer

Float

Question 45

What is the primary purpose of the 'addEventListener' method in JavaScript?

Accepted Answer

To attach an event listener to a particular HTML element

Answer

To generate a new event

Answer

To eliminate an existing event listener

Answer

To manage event handling within JavaScript code

Question 46

In JavaScript, what is the key difference between the '==' and '===' operators?

Accepted Answer

'==' checks for value equality, while '===' examines both value and type equality

Answer

'===' checks for value equality, while '==' examines both value and type equality

Answer

There is no distinction between these operators

Answer

They are interchangeable in all situations

Question 47

How do you add an event listener to an HTML element using JavaScript?

Accepted Answer

addEventListener()

Answer

onClick()

Answer

attachEvent()

Answer

onEvent()

Question 48

What is the purpose of the 'let' keyword in JavaScript?

Accepted Answer

To declare a variable with block scope

Answer

To define a function

Answer

To create an array

Answer

To store a value

Question 49

Which of the following methods is used to remove the first element from an array in JavaScript?

Accepted Answer

shift()

Answer

push()

Answer

pop()

Answer

unshift()

Question 50

Which of the following event listeners is used to detect when a user hovers over an element?

Accepted Answer

onmouseover

Answer

onclick

Answer

onload

Answer

onkeydown

Question 51

Which of the following is a valid way to write a single-line comment in JavaScript?

Accepted Answer

// this is a comment

Answer

/* this is a comment */

Answer

# this is a comment

Answer

Question 52

What is the output of the following JavaScript code: console.log(Math.min(1, 3, 5, 7));

Accepted Answer

1

Answer

3

Answer

5

Answer

7

Question 53

What is the output of the following code: console.log(typeof 'Hello')?

Accepted Answer

string

Answer

number

Answer

boolean

Answer

undefined

Question 54

What is the purpose of the 'this' keyword in JavaScript?

Accepted Answer

References the current object

Answer

Calls the current function

Answer

Creates a new object

Answer

Stores the value of the variable

Question 55

What is the output of the following JavaScript code: function sum(a, b) { return a + b; } console.log(sum(5, 10))

Accepted Answer

15

Answer

5

Answer

10

Answer

undefined

Question 56

What is the difference between '==' and '===' in JavaScript?

Accepted Answer

'==' checks for value equality, while '===' checks for both value and type equality

Answer

'==' checks for type equality, while '===' checks for value equality

Answer

'==' is used for comparing numbers, while '===' is used for comparing strings

Answer

'==' and '===' are interchangeable in JavaScript

Question 57

What is the purpose of using strict mode in JavaScript?

Accepted Answer

Prevents accidental errors by enforcing stricter coding rules

Answer

Makes code run faster

Answer

Allows for more flexible coding

Answer

Adds new features to the language

Question 58

Which JavaScript data type is used specifically for storing textual information?

Accepted Answer

String

Answer

Integer

Answer

Boolean

Answer

Array

Question 59

In JavaScript, what is the primary purpose of the 'this' keyword?

Accepted Answer

To access an object's properties

Answer

To create a new object

Answer

To pass arguments to a function

Answer

To declare a global variable

Question 60

Which event listener is used to handle a mouse click on an element?

Accepted Answer

onclick

Answer

onchange

Answer

onmouseover

Answer

onload

Question 61

What is the 'this' keyword primarily used for in JavaScript?

Accepted Answer

Referring to the current object

Answer

Creating a new object

Answer

Calling a method on the current object

Question 62

Which operator in JavaScript is used to check for strict equality?

Accepted Answer

===

Answer

==

Answer

=

Answer

!=

Question 63

Which of the following is a valid way to declare a variable in JavaScript?

Accepted Answer

var myVariable;

Answer

variable myVariable;

Answer

myVariable = 'value';

Question 64

Which of the following is a valid event listener used to respond to an event in JavaScript?

Accepted Answer

addEventListener()

Answer

attachEvent()

Answer

onEvent()