Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

alert("Hello World"); msgBox("Hello World"); console.log("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 Checks if a variable is defined Converts a variable to a string Compares two variables

Question 5

How do you declare a variable in JavaScript?

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

Question 6

Which method converts a JSON string into a JavaScript object?

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

Question 7

What does "===" mean in JavaScript?

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

Question 8

How do you create a function in JavaScript?

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

Question 9

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

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

Question 10

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

onmouseover onclick onchange onload

Question 11

How do you get the length of an array?

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

Question 12

What does "NaN" stand for?

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

Question 13

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

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

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

Question 16

What does "DOM" stand for?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

var let const constant

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