1 $Which HTML tag is used to embed JavaScript code inside a webpage?$

A.

<js>

B.

<javascript>

C.

<script>

D.

<code>

2 $Which attribute of the <script> tag is used to include an external JavaScript file?$

A.

src

B.

rel

C.

href

D.

link

3 $Where is the correct place to insert a JavaScript in an HTML document?$

A.

The <footer> section

B.

Both the <head> section and the <body> section

C.

The <head> section

D.

The <body> section

4 $What is the correct file extension for an external JavaScript file?$

A.

.script

B.

.java

C.

.html

D.

.js

5 $How do you write 'Hello World' in an alert box?$

A.

alertBox('Hello World');

B.

msgBox('Hello World');

C.

alert('Hello World');

D.

msg('Hello World');

6 $Which keyword is used to declare a variable that cannot be reassigned?$

A.

const

B.

static

C.

var

D.

let

7 $What is the scope of a variable declared with 'let' inside a block?$

A.

Global scope

B.

Block scope

C.

Function scope

D.

Module scope

8 $Which operator is used to check both value and type equality?$

A.

!=

B.

=

C.

==

D.

===

9 $What is the result of the expression: '5' + 3?$

A.

Error

B.

8

C.

53

D.

NaN

10 $Which function is used to get input from the user?$

A.

confirm()

B.

alert()

C.

input()

D.

prompt()

11 $What does the confirm() method return?$

A.

String

B.

Object

C.

Boolean

D.

Integer

12 $How does a 'while' loop start?$

A.

until (i <= 10)

B.

while (i <= 10)

C.

while i = 1 to 10

D.

while (i <= 10; i++)

13 $Which statement is used to stop a loop completely?$

A.

continue

B.

break

C.

stop

D.

return

14 $What is the purpose of the 'continue' statement?$

A.

Exits the function

B.

Skips the current iteration

C.

Restarts the loop

D.

Stops the loop execution

15 $Which loop is guaranteed to execute at least once?$

A.

do...while

B.

foreach

C.

while

D.

for

16 $How do you write an IF statement in JavaScript?$

A.

if i = 5

B.

if i == 5 then

C.

if i = 5 then

D.

if (i == 5)

17 $How do you write an IF statement for executing some code if 'i' is NOT equal to 5?$

A.

if (i <> 5)

B.

if i =! 5 then

C.

if i not 5

D.

if (i != 5)

18 $Which symbol is used for single-line comments in JavaScript?$

A.

<!-- -->

B.

**

C.

//

D.

/ /

19 $What is the correct syntax for referring to an external script called 'app.js'?$

A.

<script name='app.js'>

B.

<script src='app.js'>

C.

<script href='app.js'>

D.

<script file='app.js'>

20 $How do you create a JavaScript object?$

A.

var obj = <>;

B.

var obj = ();

C.

var obj = [];

D.

var obj = {};

21 $Given: var person = {firstName:'John', lastName:'Doe'}; How do you access the lastName?$

A.

person[lastName]

B.

person::lastName

C.

person->lastName

D.

person.lastName

22 $Which keyword is used to define a variable in JavaScript (ES5 legacy)?$

A.

dim

B.

var

C.

string

D.

int

23 $What is the correct way to write a JavaScript array?$

A.

var colors = (1:'red', 2:'green', 3:'blue')

B.

var colors = 1 = ('red'), 2 = ('green'), 3 = ('blue')

C.

var colors = ['red', 'green', 'blue']

D.

var colors = 'red', 'green', 'blue'

24 $Inside which HTML element do we put the JavaScript?$

A.

<script>

B.

<js>

C.

<scripting>

D.

<javascript>

25 $What will be the output of: typeof 'Hello'?$

A.

object

B.

string

C.

text

D.

String

26 $Which statement serves as the fall-back in a 'switch' statement?$

A.

else

B.

case

C.

break

D.

default

27 $What is the correct syntax for a 'for' loop?$

A.

for (i = 0; i <= 5)

B.

for (i <= 5; i++)

C.

for i = 1 to 5

D.

for (i = 0; i <= 5; i++)

28 $How can you add a comment that has more than one line?$

A.

// This is a comment //

B.

/ This is a comment /

C.

<!-- This is a comment -->

D.

This is a comment

29 $Which operator is used to assign a value to a variable?$

A.

-

B.

*

C.

==

D.

=

30 $What is the value of 'x' after: var x = 10; x += 5;$

A.

10

B.

15

C.

5

D.

Error

31 $Which keyword identifies a block of code to be executed if a specified condition is false?$

A.

stop

B.

break

C.

else

D.

then

32 $In an object method, what does 'this' refer to?$

A.

The global object

B.

The variable name

C.

The function itself

D.

The owner object

33 $Which logical operator represents 'OR'?$

A.

!

B.

&

C.

||

D.

&&

34 $What is the correct way to check if a variable 'car' is undefined?$

A.

if (car == null)

B.

if (car is undefined)

C.

if (car === undefined)

D.

if (typeof car == 'undefined')

35 $Which of the following is NOT a valid JavaScript variable name?$

A.

_myVar

B.

myVar2

C.

2myVar

D.

$myVar

36 $What syntax is used to access a method 'start' of an object 'engine'?$

A.

call engine.start

B.

engine.start()

C.

engine['start']

D.

engine->start()

37 $What happens if you redeclare a variable using 'let' in the same scope?$

A.

It overwrites the previous value

B.

It causes a SyntaxError

C.

It creates a new variable

D.

Nothing happens

38 $Which property is used to find the length of a string?$

A.

len

B.

count

C.

size

D.

length

39 $What is the output of Boolean(10 > 9)?$

A.

true

B.

false

C.

undefined

D.

NaN

40 $Which is the ternary operator?$

A.

||

B.

??

C.

?:

D.

&&

41 $What keyword defines a switch case block?$

A.

case

B.

if

C.

when

D.

option

42 $How do you delete a property from a JavaScript object?$

A.

remove object.property

B.

clear object.property

C.

object.property = null

D.

delete object.property

43 $Which popup box returns null if the user clicks 'Cancel'?$

A.

prompt

B.

confirm

C.

message

D.

alert

44 $What is Hoisting in JavaScript?$

A.

Looping efficiently

B.

Moving declarations to the top

C.

Deleting unused variables

D.

Moving initializations to the top

45 $Which of the following is a valid const declaration?$

A.

const PI = 3.14;

B.

const PI = 3.14; PI = 3.14159;

C.

const 3.14 = PI;

D.

const PI;

46 $What loop is best suited for iterating over the properties of an object?$

A.

for

B.

while

C.

for...in

D.

do...while

47 $Which symbol is used for the modulus (remainder) operator?$

A.

&

B.

%

C.

*

D.

/

48 $If x = 10 and y = '10', what is the result of x == y?$

A.

NaN

B.

false

C.

true

D.

undefined

49 $If x = 10 and y = '10', what is the result of x === y?$

A.

false

B.

NaN

C.

undefined

D.

true

50 $Which global object do alert(), confirm(), and prompt() belong to?$

A.

window

B.

document

C.

html

D.

console

Unit 4 - Practice Quiz