Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

alert("Hello World"); alertBox("Hello World"); console.log("Hello World"); msgBox("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 Checks if a variable is defined 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 v variableName declare 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 Equality with type coercion Not equal Strict equality (value and type)

Question 8

How do you create a function in JavaScript?

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

onload onmouseover onclick onchange

Question 11

How do you get the length of an array?

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

Question 12

What does "NaN" stand for?

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

Question 13

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

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

Question 14

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

"53" 53 8 NaN

Question 15

How do you stop a form from submitting?

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

Question 16

What does "DOM" stand for?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

const var constant let

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