Quizzes – EduHub

Question 1

What is JavaScript?

A programming language for web interactivity A styling language A markup language A database system

Question 2

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

alertBox("Hello World"); console.log("Hello World"); msgBox("Hello World"); alert("Hello World");

Question 3

Which symbol is used for single-line comments in JavaScript?

<!-- // /* #

Question 4

What does the "typeof" operator do?

Checks if a variable is defined Compares two variables Returns the data type of a variable Converts a variable to a string

Question 5

How do you declare a variable in JavaScript?

variable variableName var, let, or const declare variableName v variableName

Question 6

Which method converts a JSON string into a JavaScript object?

JSON.parse() JSON.convert() JSON.stringify() JSON.toObject()

Question 7

What does "===" mean in JavaScript?

Not equal Assignment operator Strict equality (value and type) Equality with type coercion

Question 8

How do you create a function in JavaScript?

new function myFunction() {} create myFunction() {} def myFunction() {} function myFunction() {}

Question 9

What is the correct way to write an array in JavaScript?

var colors = ["red", "green", "blue"]; var colors = red, green, blue; var colors = (1:"red", 2:"green", 3:"blue"); var colors = "red", "green", "blue";

Question 10

Which event occurs when a user clicks on an HTML element?

onmouseover onchange onload onclick

Question 11

How do you get the length of an array?

array.length array.count array.size array.len

Question 12

What does "NaN" stand for?

Null and None Negative Arithmetic Notation No Action Needed Not a Number

Question 13

Which built-in method adds an element to the end of an array?

array.unshift() array.shift() array.pop() array.push()

Question 14

What is the output of "5" + 3 in JavaScript?

NaN 8 "53" 53

Question 15

How do you stop a form from submitting?

event.cancel() event.stop() event.preventDefault() return false;

Question 16

What does "DOM" stand for?

Data Object Model Document Oriented Model Display Object Management Document Object Model

Question 17

How do you select an element by its ID in JavaScript?

document.getElementById("myId") document.querySelector(".myId") document.getElementByClass("myId") $("#myId")

Question 18

What is the purpose of "console.log()"?

Writes output to the browser console Displays an alert box Prints to the screen Logs errors only

Question 19

Which keyword is used to declare a constant variable?

var let const constant

Question 20

What is a closure in JavaScript?

A way to declare private variables only A built-in JavaScript object A loop that runs forever