1. Which of the following is not a primitive data type in JavaScript?
a) String
b) Array
c) Boolean
d) Number
Answer: b) Array
2. What keyword is used to declare a variable in JavaScript?
a) var
b) int
c) string
d) let
Answer: a) var
3. How do you create a function in JavaScript?
a) function myFunction()
b) create function myFunction()
c) new function myFunction()
d) func myFunction()
Answer: a) function myFunction()
4. Which method is used to add an element to the end of an
array in JavaScript?
a) push()
b) append()
c) addToEnd()
d) addElement()
Answer: a) push()
5. How do you access the third element in an array named
myArray?
a) myArray[2]
b) myArray[3]
c) myArray(2)
d) myArray.third()
Answer: a) myArray[2]
6. Which symbol is used for single-line comments in
JavaScript?
a) //
b) /*
c) #
d) '
Answer: a) //
7. What does the isNaN() function do in JavaScript?
a) Checks if a value is an array
b) Checks if a value is null
c) Checks if a value is not a
number
d) Checks if a value is a number
Answer: c) Checks if a value is not
a number
8. Which operator is used for strict equality comparison in
JavaScript?
a) ==
b) =
c) ===
d) !==
Answer: c) ===
9. What does the "typeof" operator do in
JavaScript?
a) Returns the type of a variable
or expression
b) Checks if a variable is defined
c) Converts a variable to a
specific type
d) Returns the length of a string
Answer: a) Returns the type of a
variable or expression
10. How do you declare a JavaScript object?
a) var myObject = {}
b) new Object myObject = {}
c) create object myObject = {}
d) object myObject = {}
Answer: a) var myObject = {}
11. Which method is used to remove the last element from an
array in JavaScript?
a) pop()
b) removeLast()
c) deleteLast()
d) removeFromEnd()
Answer: a) pop()
12. What is the result of "5" + 2 in JavaScript?
a) "7"
b) 7
c) "52"
d) Error
Answer: c) "52"
13. Which function is used to round a number down to the
nearest integer in JavaScript?
a) Math.floor()
b) Math.roundDown()
c) round()
d) floor()
Answer: a) Math.floor()
14. What is the correct syntax to include an external
JavaScript file named "script.js"?
a) <script
src="script.js">
b) <script
href="script.js">
c) <script
name="script.js">
d) <script
file="script.js">
Answer: a) <script
src="script.js">
15. How do you check if a variable is equal to either x or y
in JavaScript?
a) if (variable == x || variable ==
y)
b) if (variable = x || y)
c) if (variable === x || y)
d) if (variable == (x || y))
Answer: a) if (variable == x ||
variable == y)
16. What does the "this" keyword refer to in
JavaScript?
a) The current function
b) The parent object
c) The global object
d) The child object
Answer: b) The parent object
17. Which method is used to concatenate two or more strings
in JavaScript?
a) concat()
b) merge()
c) combine()
d) append()
Answer: a) concat()
18. What is the output of the following code: console.log(3
+ 2 + "7")?
a) 57
b) 12
c) "57"
d) Error
Answer: c) "57"
19. What is the correct syntax for an if statement in
JavaScript?
a) if (condition) { // code }
b) if {condition} // code
c) (condition) if { // code }
d) {condition} if ( // code )
Answer: a) if (condition) { // code
}
20. Which function is used to convert a string to uppercase
in JavaScript?
a) toUpperCase()
b) upperCase()
c) toUpper()
d) caseUpper()
Answer: a) toUpperCase()
21. How do you declare a JavaScript array?
a) var myArray = ()
b) var myArray = []
c) array myArray = []
d) new Array myArray = []
Answer: b) var myArray = []
22. What does the JavaScript "&&" operator
do?
a) Logical OR
b) Bitwise AND
c) Logical AND
d) Bitwise OR
Answer: c) Logical AND
23. Which method is used to find the index of a specified
item in an array in JavaScript?
a) indexOf()
b) findIndex()
c) search()
d) find()
Answer: a) indexOf()
24. What is the output of the following code:
console.log(typeof NaN)?
a) "number"
b) NaN
c) "NaN"
d) Error
Answer: a) "number"
25. How do you declare a constant variable in JavaScript?
a) const myVar = value;
b) let myVar = value;
c) var myVar = value;
d) constant myVar = value;
Answer: a) const myVar = value;
26. What does the JavaScript "!" operator do?
a) Logical NOT
b) Bitwise NOT
c) Logical OR
d) Bitwise OR
Answer: a) Logical NOT
27. Which method is used to convert a string to a number in
JavaScript?
a) parseInt()
b) toNumber()
c) parseNumber()
d) number()
Answer: a) parseInt()
28. What is the output of the following code: console.log(2
+ "2" + 2)?
a) 6
b) "222"
c) 4
d) Error
Answer: b) "222"
29. What does the "break" statement do in
JavaScript?
a) Exits the loop or switch
statement
b) Continues to the next iteration
of the loop
c) Ends the function execution
d) Skips the condition check
Answer: a) Exits the loop or switch
statement
30. How do you write a comment that spans multiple lines in
JavaScript?
a) /* This is a comment */
b) // This is a comment //
c) <!-- This is a comment -->
d) ''' This is a comment '''
Answer: a) / This is a comment /
31. What is the output of the following code: console.log(2
* 3 + "7")?
a) 77
b) "77"
c) 13
d) Error
Answer: b) "77"
32. What is the correct way to declare a JavaScript function
called "myFunction"?
a) function myFunction() {}
b) func myFunction() {}
c) create function myFunction() {}
d) new function myFunction() {}
Answer: a) function myFunction() {}
33. Which method is used to convert a number to a string in
JavaScript?
a) toString()
b) toStr()
c) numberToString()
d) stringify()
Answer: a) toString()
34. What is the output of the following code: console.log(3
== "3")?
a) true
b) false
c) Error
d) undefined
Answer: a) true
35. What does the "continue" statement do in
JavaScript?
a) Skips the condition check
b) Exits the loop or switch
statement
c) Continues to the next iteration
of the loop
d) Ends the function execution
Answer: c) Continues to the next
iteration of the loop
36. Which method is used to join the elements of an array
into a string in JavaScript?
a) concat()
b) join()
c) merge()
d) combine()
Answer: b) join()
37. What is the output of the following code: console.log(2
== "2")?
a) true
b) false
c) Error
d) undefined
Answer: a) true
38. How do you declare a block of code in JavaScript?
a) { // code }
b) block { // code }
c) block ( // code )
d) { code }
Answer: a) { // code }
39. What is the output of the following code:
console.log(typeof [1, 2, 3])?
a) "array"
b) "object"
c) "list"
d) Error
Answer: b) "object"
40. Which method is used to remove the first element from an
array in JavaScript?
a) shift()
b) removeFirst()
c) removeFromStart()
d) deleteFirst()
Answer: a) shift()
41. What is the correct way to write an if-else statement in
JavaScript?
a) if (condition) { // code } else
{ // code }
b) {condition} if { // code } else
{ // code }
c) if { // code } else (condition)
{ // code }
d) if (condition) { // code } {
else // code }
Answer: a) if (condition) { // code
} else { // code }
42. Which method is used to convert a string to lowercase in
JavaScript?
a) toLowerCase()
b) lowerCase()
c) toLower()
d) caseLower()
Answer: a) toLowerCase()
43. What is the output of the following code: console.log(4
% 2)?
a) 2
b) 0
c) 1
d) Error
Answer: b) 0
44. What is the correct way to write a for loop in
JavaScript?
a) for (var i = 0; i < 10; i++)
{ // code }
b) loop (var i = 0; i < 10; i++)
{ // code }
c) iterate (var i = 0; i < 10;
i++) { // code }
d) for (i = 0; i < 10; i++) { //
code }
Answer: a) for (var i = 0; i <
10; i++) { // code }
45. What is the output of the following code: console.log(2
+ 2 + "2")?
a) 6
b) "22"
c) 4
d) Error
Answer: b) "22"
46. What is the correct way to write a while loop in
JavaScript?
a) while (condition) { // code }
b) iterate (condition) { // code }
c) loop (condition) { // code }
d) for (condition) { // code }
Answer: a) while (condition) { //
code }
47. Which method is used to sort the elements of an array in
JavaScript?
a) sort()
b) arrange()
c) order()
d) organize()
Answer: a) sort()
48. What is the output of the following code:
console.log("5" - 2)?
a) 7
b) "7"
c) 3
d) Error
Answer: c) 3
49. What does the JavaScript "||" operator do?
a) Logical OR
b) Bitwise OR
c) Logical AND
d) Bitwise AND
Answer: a) Logical OR
50. Which method is used to return the length of a string in
JavaScript?
a) length()
b) len()
c) count()
d) size()
Answer: a) length()
