JavaScript Quiz

1. What does JavaScript do?

It is used for creating web pages.
It is used for creating database queries.
It is used for creating server-side applications.
It is used for styling web pages.

Answer: It is used for creating web pages.

2. How do you display a message in the browser's console?

console.log("Hello World");
print("Hello World");
alert("Hello World");
echo("Hello World");

Answer: console.log("Hello World");

3. What is a JavaScript statement?

A statement performs an action.
A statement is a block of code that repeats.
A statement is a function that can be called.
A statement is used to define variables.

Answer: A statement performs an action.

4. What is the correct syntax to create a function in JavaScript?

function myFunction() { }
createFunction myFunction() { }
function: myFunction() { }
def myFunction() { }

Answer: function myFunction() { }

5. How do you write a single-line comment in JavaScript?

// This is a comment

/* This is a comment */
# This is a comment

Answer: // This is a comment

6. How do you declare a variable in JavaScript?

var x;
variable x;
let x;
const x;

Answer: var x;

7. What does the '==' operator do in JavaScript?

Compares two values for equality.
Assigns a value to a variable.
Compares two variables.
Adds two values.

Answer: Compares two values for equality.

8. What will the expression 5 + 10 + "10" evaluate to in JavaScript?

1510
25
15
30

Answer: 1510

9. What is the data type of the following value: 42?

Number
String
Boolean
Object

Answer: Number

10. How do you call a function named "myFunction" in JavaScript?

myFunction();
call myFunction();
function myFunction();
invoke myFunction();

Answer: myFunction();

11. How do you access the value of the "name" property of an object in JavaScript?

object.name
object["name"]
object.get("name")
object:name

Answer: object.name

12. Which event is triggered when the user clicks on an HTML element?

onclick
onload
onhover
onfocus

Answer: onclick

13. How do you get the length of a string in JavaScript?

string.length
string.size
string.count
string[0]

Answer: string.length

14. How do you generate a random number between 0 and 1 in JavaScript?

Math.random()
random()
Math.random(0,1)
Math.generateRandom()

Answer: Math.random()

15. How do you round a number to the nearest integer in JavaScript?

Math.round()
round()
Math.floor()
Math.ceil()

Answer: Math.round()

16. What happens to variables declared using var before they are initialized in JavaScript?

They are hoisted to the top.
They throw an error.
They are undefined.
They are blocked from access.

Answer: They are hoisted to the top.

17. What is the correct syntax for an arrow function in JavaScript?

const myFunction = () => { }
const myFunction = function() { }
const myFunction = { }
const myFunction = -> { }

Answer: const myFunction = () => { }

18. How do you access an element with the ID "myElement" in JavaScript?

document.getElementById("myElement")
document.querySelector("#myElement")
document.getElementByIdByName("myElement")
document.querySelectorElement("myElement")

Answer: document.getElementById("myElement")

19. How do you define a class in JavaScript?

class MyClass { }
function MyClass { }
MyClass { }
object MyClass { }

Answer: class MyClass { }

20. How do you import a module in JavaScript?

import myModule from './myModule.js';
require('./myModule.js');
include('./myModule.js');
import './myModule.js';

Answer: import myModule from './myModule.js';