Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

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

Question 3

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

/* // <!-- #

Question 4

What does the "typeof" operator do?

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

Question 5

How do you declare a variable in JavaScript?

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

Question 6

Which method converts a JSON string into a JavaScript object?

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

Question 7

What does "===" mean in JavaScript?

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

Question 8

How do you create a function in JavaScript?

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

Question 9

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

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

Question 10

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

onchange onload onclick onmouseover

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?

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

Question 13

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

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

Question 14

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

"53" 8 53 NaN

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?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

const constant let var

Question 20

What is a closure in JavaScript?

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