Free Printable JavaScript

Worksheets

JavaScript

Total questions: 70

Worksheet time: 35mins

Name

Class

Date

How do you write "Hello World" in an alert box?

msg("Hello World");

alertBox("Hello World");

alert("Hello World");

alert("Hello World")

JavaScript code can be written directly into an HTML document using the (a) tag.

Which of the following is a primitive data type in JavaScript?

Array

Object

Function

String

Which value is returned if you compare two distinct objects in JavaScript using the equality (==) operator?

true

false

undefined

NaN

Which of the following keywords is used to declare a variable in JavaScript?

var

let

const

All of the above

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

Function scope

Block scope

Global scope only

None of the above

How can you create a constant variable that cannot be reassigned in JavaScript?

const variableName;

constant variableName;

var const variableName;

let const variableName

What will be the output of the following code snippet?

let a = 5;

let b = a;
a = 10;

console.log(b);

(a)

Which method can be used to convert a string to an integer in JavaScript?

parseInt()

toString()

Number()

parseFloat(

10.

What is the data type of null in JavaScript?

(a)

11.

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

Boolean

Number

Symbol

Array

12.

True or False

In JavaScript, you can change the value of a variable declared with const after it is initialized.

(a)

13.

True or False

The typeof operator can be used to determine the type of a variable.

(a)

14.

True or False

null is strictly equal to undefined in JavaScript.

(a)

15.

In JavaScript, the (a) operator is used to determine the data type of a variable.

16.

Variables declared with let and const have (a) scope.

17.

A variable that is declared but not initialized will have the value (a) .

18.

The (a) function is used to convert a string to a floating-point number.

19.

What will be the output of the following code snippet?

var x = 3;

var y = x;

x - 7;

console.log(y);

(a)

20.

What will be the output of the following code snippet?

const c = 10;

let d = c;

20-d

console.log(c);

(a)

21.

What will be the output of the following code snippet?

let e = 'hello';

let f = e;

e = 'world';

console.log(f);

(a)

22.

What will be the output of the following code snippet?

let arr1 = [1, 2, 3];

let arr2 = arr1;

arr1.push(4);

console.log(arr2);

(a)

23.

What will be the output of the following code snippet?

let obj1 = { a: 1 };

let obj2 = obj1;

obj1.a = 5;

console.log(obj2.a);

(a)

24.

What will be the output of the following code snippet?

let g = [1, 2];

let h = [...g];

g.push(3);

console.log(h);

(a)

25.

What will the following expression evaluate to?

3 + 2 * 2

(a)

26.

Which operator is used to concatenate two strings in JavaScript?

27.

Which of the following operators has the highest precedence?

28.

What will the following expression evaluate to?

4 + 5 + "7"

(a)

29.

Which operator is used to compare both value and type in JavaScript?

===

30.

What will the following expression evaluate to?

10 % 3

(a)

31.

Which operator is used to increment a variable in JavaScript?

(a)

32.

True or False

The addition operator (+) has a higher precedence than the multiplication operator (*) in JavaScript

(a)

33.

The logical OR operator (||) has lower precedence than the logical AND operator (&&).

(a)

34.

The (a) operator is used to find the remainder of a division operation.

35.

True or False:

The for loop is typically used when the number of iterations is known beforehand.

(a)

36.

In JavaScript, the do...while loop is an example of a (a) loop.

37.

Which of the following methods adds elements to the end of an array?

push()

pop()

shift()

unshift()

38.

True or False:

Arrays in JavaScript can hold elements of different data types.

(a)

39.

Arrays are indexed starting from (a) .

40.

Which method removes the first element from an array and returns it?

shift()

unshift(

pop()

push()

41.

Array.isArray(myArray) returns true if myArray is an array.

True

False

42.

Which method returns the index within the calling String object of the first occurrence of the specified value?

indexOf()

lastIndexOf()

search()match()

43.

In JavaScript, the while loop executes a block of code as long as a specified (a) is true.

44.

Which loop executes a block of code at least once, and then repeats the loop as long as a specified condition is true?

do...while

for...in

while

for

45.

True or False:

break statement is used to terminate the execution of a loop.

(a)

46.

The Math.random() function generates a random number between ... and ....

1 & 5

0 & 1

5 &10

0 & 9

47.

The .map() method modifies the original array.

True

False

Both

No answer

48.

Which method is used to find the length of a string in JavaScript?

length

.length()

length()

All the above

49.

Which method is used to find the length of a string in JavaScript?

length

.length()

length()

All the above

50.

Which of the following methods is used to concatenate two strings?

(a)

51.

What will be the output of the following code?

let str = "Hello, World!";

console.log(str.toUpperCase());

(a)

52.

What does the .includes() method do in JavaScript?

Checks if a string contains a specified value

Finds the index of a value

Splits a string into an array

Replaces a part of a string

53.

What does the .includes() method do in JavaScript?

Checks if a string contains a specified value

Finds the index of a value

Splits a string into an array

Replaces a part of a string

54.

What will be the output of the following code?

let str = "JavaScript";

console.log(str.charAt(4));

(a)

55.

How do you replace "Hello" with "Hi" in a string?

str.replace("Hello", "Hi")

str.change("Hello", "Hi")

str.swap("Hello", "Hi")

str.modify("Hello", "Hi")

56.

Which method is used to split a string into an array?

(a)

57.

What does the break statement do in a loop?

Skips one iteration

Stops the loop completely

Restarts the loop

Throws an error

58.

What does the Math.max(2, 8, 5, 10, 3) function return?

(a)

59.

Which of the following is NOT a valid DOM collection type?

ElementArray

All are valid

HTMLCollection

NodeList

60.

Which property returns the number of child elements a DOM element has?

childElementCount

childNodes.length

children.count

element.childCount

61.

What is the purpose of querySelectorAll()?

To select all elements matching a CSS selector

To create new DOM elements

To remove elements from the DOM

To select a single element

62.

Which property is used to modify the CSS styles of a DOM element?

element.style

element.css

element.className

element.id

63.

Which method returns a collection of elements with a specific class name?

document.getElementsByClassName()

document.querySelectorAll()

document.getElementById()

document.getElementsByTagName()

64.

What does DOM stand for?

(a)

65.

Which keyword is used to wait for a Promise to resolve inside an async function?

wait

yield

await

pause

66.

What is the primary advantage of asynchronous programming in JavaScript?

It prevents blocking the main thread

It executes code sequentially

It makes all operations synchronous

It reduces code complexity

67.

Which of the following correctly defines a function using a function declaration?

function myFunc() {}

function: myFunc() {}

var myFunc = () => {}

def myFunc() {}

68.

How do you create an instance of a class?

MyClass.new();

new MyClass();

MyClass();

MyClass.create();

69.

What is the purpose of the extends keyword in a JavaScript class?

To define a static method

To inherit from a parent class

To bind methods permanently

To encapsulate private properties

70.

How do you properly write a while loop?

while (i < 10) {}

while { i < 10 }

while i < 10 {}

while i = 10 {}

Reset

JavaScript

Total questions: 70

Worksheet time: 35mins

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