Beginner JavaScript Questions

Question 1

How do you add an element to the beginning of an array?

Accepted Answer

array.unshift(element)

Question 2

Which method is used to find the length of an array?

Accepted Answer

array.length

Question 3

How do you change the text of an HTML element in JavaScript?

Accepted Answer

element.textContent = "new text";

Question 4

How do you check if two values are equal in type and value?

Accepted Answer

===

Question 5

What does document.getElementById("myID") do?

Accepted Answer

Selects an element by its ID

Question 6

How do you access the first element of an array?

Accepted Answer

array[0]

Question 7

What is undefined in JavaScript?

Accepted Answer

A variable that has been declared but not assigned a value

Question 8

How do you create a constant in JavaScript?

Accepted Answer

const myConstant = value;

Question 9

Which of the following is NOT a JavaScript data type?

Accepted Answer

Integer

Question 10

What does Math.random() do?

Accepted Answer

Returns a random number between 0 and 1

Question 11

How do you select all elements with a specific class name?

Accepted Answer

document.querySelectorAll(".classname")

Question 12

What does document.querySelector() do?

Accepted Answer

Selects the first matching element

Question 13

What does return do in a function?

Accepted Answer

Stops the function and gives back a value

Question 14

What does NaN stand for?

Accepted Answer

Not-a-Number

Question 15

Which method removes the last element of an array?

Accepted Answer

pop()

Question 16

How do you combine strings in JavaScript?

Accepted Answer

Use the + operator

Question 17

What is the output of 5 + "5"?

Accepted Answer

"55"

Question 18

What is the purpose of break in a loop?

Accepted Answer

To stop the loop

Question 19

How do you convert a string to a number?

Accepted Answer

Number(string)

Question 20

How do you remove the first element of an array?

Accepted Answer

array.shift()

Question 21

What is a boolean in JavaScript?

Accepted Answer

A value that is either true or false

Question 22

How do you write a function in JavaScript?

Accepted Answer

function myFunction() {}

Question 23

What is the output of typeof "Hello"?

Accepted Answer

string

Question 24

Which method adds an item to the end of an array?

Accepted Answer

push()

Question 25

How do you loop through an array in JavaScript?

Accepted Answer

for (let i = 0; i < array.length; i++) {}

Question 26

What does === mean in JavaScript?

Accepted Answer

Strict equality

Question 27

What is JavaScript?

Accepted Answer

A programming language for web development

Question 28

How do you declare a variable in JavaScript?

Accepted Answer

let, const, or var

Question 29

What is the purpose of a loop?

Accepted Answer

To repeat code

Question 30

What is an array in JavaScript?

Accepted Answer

A collection of values

Question 31

What is a string in JavaScript?

Accepted Answer

A sequence of characters

Question 32

What is the result of typeof null?

Accepted Answer

object

Question 33

How do you write an if statement?

Accepted Answer

if (condition) {}

Question 34

How do you write a comment in JavaScript?

Accepted Answer

// This is a comment

Question 35

What is the default value of an uninitialized variable?

Accepted Answer

undefined

Question 36

What does console.log() do?

Accepted Answer

Outputs a message to the console

Question 37

What is the purpose of the break statement in a loop?

Accepted Answer

Stops the loop entirely

Question 38

Which keyword is used to create a loop in JavaScript?

Accepted Answer

for

Question 39

How do you skip the current iteration of a loop?

Accepted Answer

continue

Question 40

How do you check if a value is NaN?

Accepted Answer

isNaN(value)

Beginner JavaScript Questions

Questions 40

Beginner JavaScript Questions

Questions 40