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Please answer the following 50 multiple-choice questions to test your knowledge in JavaScript fundamentals. You must place your answer file in the submission folder. Within the submission/Q1/set_a folder, create a folder called your github_id.
-
What is JavaScript primarily used for?
- a) Creating stylish webpage layouts
- b) Adding interactivity to websites
- c) Storing and managing databases
- d) Designing server infrastructure
-
Which keyword is used to declare a variable in JavaScript?
- a)
var - b)
let - c)
const - d) All of the above
- a)
-
Which data type is not supported in JavaScript?
- a) Numbers
- b) Strings
- c) Booleans
- d) Characters
-
What is the result of
typeof nullin JavaScript?- a)
"null" - b)
"object" - c)
"undefined" - d)
"string"
- a)
-
How do you add a comment in JavaScript?
- a)
// This is a comment - b)
/* This is a comment */ - c)
<!-- This is a comment --> - d)
# This is a comment
- a)
-
Which operator is used for concatenating strings in JavaScript?
- a)
+ - b)
- - c)
* - d)
/
- a)
-
What is the output of
2 + "2"in JavaScript?- a)
4 - b)
"22" - c)
"4" - d)
NaN
- a)
-
Which statement is used to exit a loop in JavaScript?
- a)
break - b)
continue - c)
return - d)
exit
- a)
-
What does the
document.getElementById()method in JavaScript do?- a) Retrieves an element by its class name
- b) Retrieves an element by its tag name
- c) Retrieves an element by its id
- d) Retrieves an element by its attribute
-
Which function is used to convert a string to an integer in JavaScript?
- a)
parseInt() - b)
parseFloat() - c)
toFixed() - d)
toString()
- a)
-
How do you declare a function in JavaScript?
- a)
function myFunction() {} - b)
var myFunction() {} - c)
const myFunction() {} - d)
let myFunction() {}
- a)
-
What is the result of
5 == "5"in JavaScript?- a)
true - b)
false - c)
undefined - d)
NaN
- a)
-
Which method is used to remove the last element from an array in JavaScript?
- a)
pop() - b)
push() - c)
shift() - d)
unshift()
- a)
-
What does the
setTimeout()function do in JavaScript?- a) Pauses the execution of the code for a specified duration
- b) Executes a function after a specified delay
- c) Adds an event listener to an element
- d) Modifies the style of an element
-
What is the purpose of the
thiskeyword in JavaScript?- a) Refers to the current object or context
- b) Declares a new variable
- c) Defines a JavaScript class
- d) Accesses an external API
-
How do you check the length of an array in JavaScript?
- a)
length() - b)
count() - c)
size() - d)
length
- a)
-
Which method is used to convert a JavaScript object to a JSON string?
- a)
parse() - b)
stringify() - c)
convert() - d)
serialize()
- a)
-
What does the
NaNvalue represent in JavaScript?- a) "Not a Number"
- b) "Null and Notable"
- c) "Negative Arithmetic Number"
- d) "No Action Necessary"
-
How do you create a new object in JavaScript?
- a)
new Object() - b)
createObject() - c)
Object.create() - d) All of the above
- a)
-
Which keyword is used to throw an exception in JavaScript?
- a)
exception - b)
error - c)
throw - d)
catch
- a)
-
What is the output of
typeof []in JavaScript?- a)
"array" - b)
"object" - c)
"array-object" - d)
"undefined"
- a)
-
Which operator is used to check for strict equality in JavaScript?
- a)
== - b)
!= - c)
=== - d)
!==
- a)
-
What does the
splice()method do in JavaScript?- a) Adds elements to the beginning of an array
- b) Removes elements from an array
- c) Sorts the elements of an array
- d) Converts an array to a string
-
Which method is used to add a new element to the end of an array in JavaScript?
- a)
push() - b)
pop() - c)
shift() - d)
unshift()
- a)
-
How do you access the length of a string in JavaScript?
- a)
length() - b)
size() - c)
count() - d)
length
- a)
-
Which method is used to convert a string to uppercase in JavaScript?
- a)
toUpperCase() - b)
toLowerCase() - c)
trim() - d)
charAt()
- a)
-
What does the
addEventListener()method do in JavaScript?- a) Modifies the style of an element
- b) Removes an event listener from an element
- c) Adds an event listener to an element
- d) Retrieves an element by its id
-
How do you round a number to the nearest integer in JavaScript?
- a)
round() - b)
floor() - c)
ceil() - d)
toFixed()
- a)
-
What is the purpose of the
map()method in JavaScript?- a) Iterates over the elements of an array and performs a callback function on each element
- b) Removes elements from an array based on a specified condition
- c) Sorts the elements of an array in ascending order
- d) Converts an array to a string
-
Which operator is used to access a property of an object in JavaScript?
- a)
: - b)
. - c)
=> - d)
@
- a)
-
What is the output of
console.log(typeof NaN)in JavaScript?- a)
"number" - b)
"undefined" - c)
"NaN" - d)
"object"
- a)
-
How do you convert a JavaScript object to an array?
- a)
Object.values() - b)
Object.keys() - c)
Object.entries() - d) All of the above
- a)
-
What does the
substring()method do in JavaScript?- a) Extracts a section of a string and returns a new string
- b) Removes leading and trailing spaces from a string
- c) Converts a string to uppercase
- d) Converts a string to lowercase
-
Which method is used to sort the elements of an array in JavaScript?
- a)
sort() - b)
reverse() - c)
concat() - d)
slice()
- a)
-
How do you convert a string to an array in JavaScript?
- a)
split() - b)
join() - c)
concat() - d)
splice()
- a)
-
What is the output of
console.log(2 + 2 + "2")in JavaScript?- a)
"4" - b)
"22" - c)
"222" - d)
"NaN"
- a)
-
What is the purpose of the
reduce()method in JavaScript?- a) Applies a callback function against an accumulator and each element in an array to reduce it to a single value
- b) Filters the elements of an array based on a specified condition
- c) Adds new elements to the beginning of an array
- d) Reverses the order of the elements in an array
-
How do you check if a variable is an array in JavaScript?
- a)
Array.isArray() - b)
typeof - c)
instanceof - d)
isArray()
- a)
-
Which method is used to remove leading and trailing spaces from a string in JavaScript?
- a)
trim() - b)
toUpperCase() - c)
toLowerCase() - d)
charAt()
- a)
-
What does the
toFixed()method do in JavaScript?- a) Returns the specified number of decimal places as a string
- b) Rounds a number to the nearest integer
- c) Returns the square root of a number
- d) Returns the absolute value of a number
-
How do you access the value of an input field in JavaScript?
- a)
document.getValue() - b)
inputField.value - c)
inputField.getValue() - d)
document.getElement(inputField).value
- a)
-
Which method is used to find the index of a specified value in an array in JavaScript?
- a)
indexOf() - b)
findIndex() - c)
search() - d)
includes()
- a)
-
What is the output of
console.log(2 * "2")in JavaScript?- a)
4 - b)
"4" - c)
"22" - d)
NaN
- a)
-
How do you convert a number to a string in JavaScript?
- a)
String() - b)
Number.toString() - c)
parseInt() - d)
toFixed()
- a)
-
What does the
Math.random()function do in JavaScript?- a) Returns a random integer between 0 and 1
- b) Generates a random number between a specified range
- c) Returns the square root of a number
- d) Rounds a number to the nearest integer
-
Which method is used to remove an event listener from an element in JavaScript?
- a)
removeEventListener() - b)
addEventListener() - c)
getElementById() - d)
querySelector()
- a)
-
How do you convert a string to lowercase in JavaScript?
- a)
toLowerCase() - b)
toUpperCase() - c)
trim() - d)
charAt()
- a)
-
What is the output of
console.log(5 > 2 && 3 < 6)in JavaScript?- a)
true - b)
false - c)
undefined - d)
NaN
- a)
-
Which method is used to find the highest value in an array in JavaScript?
- a)
Math.max() - b)
Math.min() - c)
findMax() - d)
findMin()
- a)
-
How do you convert a string to uppercase in JavaScript?
- a)
toUpperCase() - b)
toLowerCase() - c)
trim() - d)
charAt()
- a)
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