Quizzes – EduHub

Question 1

What is JavaScript?

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

Question 2

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

alert("Hello World"); msgBox("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?

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 declare variableName var, let, or const v variableName

Question 6

Which method converts a JSON string into a JavaScript object?

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

Question 7

What does "===" mean in JavaScript?

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

Question 8

How do you create a function in JavaScript?

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

Question 11

How do you get the length of an array?

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

Question 12

What does "NaN" stand for?

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

Question 13

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

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

Question 14

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

"53" 53 NaN 8

Question 15

How do you stop a form from submitting?

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

Question 16

What does "DOM" stand for?

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

Question 17

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

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

Question 18

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

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

Question 19

Which keyword is used to declare a constant variable?

var constant const let

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