JavaScript Fundamentals: Interactive Quizzes for Sixth Form

Question 1

What is the distinction between an 'if' statement and a 'switch' statement in JavaScript?

Accepted Answer

Switch statements check for multiple conditions, while if statements check for a single condition.

Answer

If statements check for multiple conditions, while switch statements check for a single condition.

Answer

There is no difference.

Answer

If statements are used for conditional execution, while switch statements are used for branching.

Question 2

What is the purpose of a 'while' loop in JavaScript?

Accepted Answer

To execute a block of code repeatedly while a condition is true.

Answer

To execute a block of code a fixed number of times.

Answer

To execute a block of code only once.

Answer

To stop the execution of a loop.

Question 3

What is the difference between a 'parameter' and an 'argument' in JavaScript?

Accepted Answer

A parameter is a variable defined in a function, while an argument is a value passed to the function when it is called.

Answer

An argument is a variable defined in a function, while a parameter is a value passed to the function when it is called.

Answer

There is no difference between a parameter and an argument in JavaScript.

Question 4

What is the primary purpose of an 'event listener' in JavaScript?

Accepted Answer

To listen for specified events (e.g., clicks, mouse movements) and execute code when those events occur.

Answer

To create new events that can be triggered by user interactions.

Answer

To prevent events from happening.

Question 5

What is the DOM (Document Object Model) in JavaScript?

Accepted Answer

A tree-like representation of the HTML document that allows JavaScript to access, modify, and manipulate its elements.

Answer

A library that provides additional functionality to JavaScript.

Answer

A way to create new HTML elements.

Question 6

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

Accepted Answer

To display messages in the browser's console.

Answer

To store data in the browser's memory.

Answer

To create new HTML elements.

Question 7

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

Accepted Answer

To declare and optionally initialize a variable

Answer

To assign a value to a variable

Answer

To create a function

Answer

To specify the scope of a variable

Question 8

What is the difference between an 'event listener' and an 'event handler' in JavaScript?

Accepted Answer

An event listener listens for an event, while an event handler responds to it.

Answer

An event handler listens for an event, while an event listener responds to it.

Answer

They are the same thing.

Answer

An event listener is for client-side events, while an event handler is for server-side events.

Question 9

Which of the following is the correct selector in JavaScript to select elements with a specific class name?

Accepted Answer

.className

Answer

#className

Answer

className

Answer

[class=className]

Question 10

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

Accepted Answer

To add an event listener to an element

Answer

To remove an event listener from an element

Answer

To create an event object

Answer

To handle an event

Question 11

What is the output of the following JavaScript code: console.log(typeof null);

Accepted Answer

object

Answer

null

Answer

undefined

Answer

string

Question 12

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

Accepted Answer

To refer to the current object

Answer

To refer to the global object

Answer

To create a new object

Answer

To access properties of the window object

Question 13

What is a potential disadvantage of using asynchronous programming in JavaScript?

Accepted Answer

Increased complexity of code

Answer

Enhanced responsiveness

Answer

Efficient utilization of resources

Question 14

What is the 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 assign a value to a variable

Question 15

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

Accepted Answer

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

Answer

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

Answer

They do the same thing

Answer

One is for numbers and the other for strings

Question 16

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

Accepted Answer

To get an element by its ID

Answer

To create a new element

Answer

To remove an element from the DOM

Answer

To add an event listener to an element

Question 17

What does the 'JSON.stringify()' method do in JavaScript?

Accepted Answer

Convert a JavaScript object to a JSON string

Answer

Convert a JSON string to a JavaScript object

Answer

Validate a JSON string

Answer

Parse a JSON string

Question 18

What is the main purpose of a variable in JavaScript?

Accepted Answer

To store data

Answer

To perform calculations

Answer

To control program flow

Answer

To handle user events

Question 19

Which of the following is the correct syntax to define a function in JavaScript?

Accepted Answer

function name(parameters) { ... }

Answer

def name(parameters) { ... }

Answer

func name(parameters) { ... }

Answer

create name(parameters) { ... }

Question 20

What is the difference between an event listener and an event handler in JavaScript?

Accepted Answer

An event listener monitors for an event, while an event handler responds to an event.

Answer

An event handler monitors for an event, while an event listener responds to an event.

Answer

They are the same thing.

Answer

There is no difference between them.

Question 21

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

Accepted Answer

To refer to the current object

Answer

To refer to the parent object

Answer

To refer to the child object

Answer

To refer to the global object

Question 22

Which of the following is NOT a loop structure in JavaScript?

Accepted Answer

if

Answer

for

Answer

while

Answer

do...while

Question 23

What is the purpose of a conditional statement in JavaScript?

Accepted Answer

To control the flow of execution

Answer

To perform calculations

Answer

To store data

Answer

To handle user events

Question 24

What is the difference between a local variable and a global variable in JavaScript?

Accepted Answer

A local variable is only accessible within a function, while a global variable is accessible throughout the program.

Answer

A global variable is only accessible within a function, while a local variable is accessible throughout the program.

Answer

They are the same thing.

Answer

There is no difference between them.

Question 25

In JavaScript, how does the 'this' keyword typically behave within functions that are used as event listeners?

Accepted Answer

It refers to the element that triggered the event.

Answer

It refers to the window object.

Answer

It refers to the document object.

Question 26

Which JavaScript method allows you to create a new array with only the elements that meet a specific condition?

Accepted Answer

filter()

Answer

map()

Answer

reduce()

Question 27

In JavaScript, which declaration below defines a variable correctly?

Accepted Answer

let myVariable;

Answer

int myVariable;

Answer

var 123myVariable;

Answer

variable myVariable = 'value';

Question 28

What is the main purpose of the `function` keyword in JavaScript?

Accepted Answer

To define a reusable block of code.

Answer

To generate a new object.

Answer

To declare a variable.

Answer

To print data to the console.

Question 29

Which of the following methods can be used to add an element to an array in JavaScript?

Accepted Answer

push()

Answer

add()

Answer

insert()

Answer

append()

Question 30

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

Accepted Answer

To select a single element from the DOM.

Answer

To select all elements with a given class name.

Answer

To create a new element in the DOM.

Answer

To remove an element from the DOM.

Question 31

What is the primary purpose of a variable in JavaScript?

Accepted Answer

To store data for later use

Answer

To define a function

Answer

To create an event listener

Answer

To style HTML elements

Question 32

Explain the difference between an event and an event listener.

Accepted Answer

An event is an action that occurs, while an event listener listens for and responds to the event

Answer

An event listener triggers an action, while an event responds to it

Answer

An event is a type of event listener, while an event listener is a type of event

Answer

There is no difference between an event and an event listener

Question 33

Which of the following is NOT a valid comparison operator in JavaScript?

Accepted Answer

=

Answer

==

Answer

!=

Answer

<

Question 34

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

Accepted Answer

To refer to the current object

Answer

To define a new object

Answer

To call a function

Answer

To create a variable

Question 35

Explain the difference between local and global variables in JavaScript.

Accepted Answer

Local variables can only be accessed within the function they are declared, while global variables can be accessed from anywhere in the program

Answer

Global variables can only be accessed within the function they are declared, while local variables can be accessed from anywhere in the program

Answer

Local and global variables are the same

Answer

There is no difference between local and global variables

Question 36

Which of the following is the correct way to add an event listener to an HTML element in JavaScript?

Accepted Answer

element.addEventListener('event', function) {}

Answer

element.addEvent('event', function) {}

Answer

element.attachEvent('event', function) {}

Answer

element.onEvent = function() {}

Question 37

In JavaScript, which fundamental principle of object-oriented programming (OOP) involves bundling data and methods together within objects?

Accepted Answer

Encapsulation

Answer

Dynamic type checking

Answer

Automatic memory management

Answer

Multiple inheritance

Question 38

Which event listener is used to detect when a user clicks an element?

Accepted Answer

onclick

Answer

onchange

Answer

onhover

Answer

onsubmit

Question 39

What will be the output of the following JavaScript code: `console.log(typeof 10)`?

Accepted Answer

Number

Answer

String

Answer

Integer

Answer

Float

Question 40

Which of the following is **not** a valid comparison operator in JavaScript?

Accepted Answer

>>

Answer

==

Answer

!=

Answer

===

Question 41

What is the output of the following JavaScript code: `console.log(Math.sqrt(16))`?

Accepted Answer

4

Answer

2

Answer

8

Answer

16

Question 42

What is the primary purpose of the `return` statement in JavaScript?

Accepted Answer

To end the execution of a function and potentially return a value

Answer

To create a new object

Answer

To store a value

Answer

To handle user input

Question 43

Which of the following is a valid JavaScript variable name?

Accepted Answer

myVariable

Answer

-myVariable

Answer

1myVariable

Answer

my-variable

Question 44

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

Accepted Answer

To define a reusable block of code

Answer

To declare a variable

Answer

To create a new object

Answer

To handle events

Question 45

Which of the following is an event listener in JavaScript?

Accepted Answer

onclick

Answer

oncreate

Answer

ondefine

Answer

onloop

Question 46

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

Accepted Answer

To refer to the current object

Answer

To call a function

Answer

To access object properties

Answer

To declare a global variable

Question 47

What is the key difference between an 'if' statement and a 'switch' statement in JavaScript?

Accepted Answer

An 'if' statement evaluates only one condition, while a 'switch' statement evaluates multiple conditions.

Answer

An 'if' statement is used for logical conditions, while a 'switch' statement is used for arithmetic conditions.

Question 48

Which of the following is a valid event listener in JavaScript?

Accepted Answer

click

Answer

listen

Answer

trigger

Answer

event

Question 49

What is the primary difference between the 'innerHTML' and 'innerText' properties in JavaScript?

Accepted Answer

innerHTML includes HTML tags, while innerText does not.

Answer

innerHTML is read-only, while innerText is writable.

Answer

innerHTML is used to modify the appearance of an element, while innerText is used to modify its content.

Question 50

What is the purpose of the 'document' object in JavaScript?

Accepted Answer

To represent the entire HTML document

Answer

To represent the body of the HTML document

Answer

To represent the head of the HTML document

Answer

To represent the current window