Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

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

Question 3

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

# /* <!-- //

Question 4

What does the "typeof" operator do?

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

Question 5

How do you declare a variable in JavaScript?

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

Question 6

Which method converts a JSON string into a JavaScript object?

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

Question 7

What does "===" mean in JavaScript?

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

Question 8

How do you create a function in JavaScript?

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

onclick onmouseover onchange onload

Question 11

How do you get the length of an array?

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

Question 12

What does "NaN" stand for?

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

Question 13

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

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

Question 14

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

8 53 NaN "53"

Question 15

How do you stop a form from submitting?

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

Question 16

What does "DOM" stand for?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

const let var constant

Question 20

What is a closure in JavaScript?

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