Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

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

Checks if a variable is defined Returns the data type of a variable Compares two variables 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.toObject() JSON.stringify()

Question 7

What does "===" mean in JavaScript?

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

Question 8

How do you create a function in JavaScript?

new function myFunction() {} function myFunction() {} create 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 onload onchange onmouseover

Question 11

How do you get the length of an array?

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

Question 12

What does "NaN" stand for?

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

Question 13

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

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

Question 14

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

8 53 "53" NaN

Question 15

How do you stop a form from submitting?

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

Question 16

What does "DOM" stand for?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

constant let var const

Question 20

What is a closure in JavaScript?

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