Tough Moodle Test - 76+ MCQs: Moodle test: Challenge Your Knowledge with a Comprehensive JavaScript Exam

1. What is the output of the expression '3' + 2 + 1 in JavaScript?

'321'

'6'

'32'

2. In JavaScript, what does the 'finally' block do in a try-catch-finally statement?

Executes code after try and catch, regardless of the outcome

Executes code before try and catch

Executes code only if an error occurs

Executes code only if no error occurs

3. What is the result of the expression '5' + 3 in JavaScript?

NaN

4. What is the primary function of the 'typeof' operator in JavaScript?

To check if a variable is defined

To return the data type of a variable

To convert a string to a number

To concatenate two strings

5. Which method removes the last element from an array and returns that element?

pop()

remove()

delete()

splice()

6. What does the 'parseInt()' function do in JavaScript?

Parses a string and returns an integer

Returns the integer part of a number

Rounds a number to the nearest integer

Converts a number to a string

7. How do you declare a variable in JavaScript?

var myVar;

variable myVar;

let myVar = ;

myVar = ;

8. What does the 'async' keyword do in a function declaration?

Makes the function asynchronous

Throws an error

Pauses the function execution

None of the above

9. Which event fires when an HTML element loses focus?

onblur

onfocus

onchange

onlose

10. What does the 'typeof' operator return for a null value?

'null'

'object'

'undefined'

'string'

11. What is the purpose of the 'this' keyword in JavaScript?

To refer to the current function

To refer to the global object

To refer to the parent function

To refer to the current object

12. What is the purpose of the 'Symbol' data type introduced in ES6?

To create unique identifiers

To store complex data structures

To represent strings

To handle mathematical operations

13. How can you deep clone an object in JavaScript?

Using the JSON methods

Using the Object.assign() method

Using loops

All of the above

14. What does the 'continue' statement do in a loop?

Terminates the loop

Skips the rest of the loop and continues with the next iteration

Throws an error

None of the above

15. What is the result of the following code? ```javascript console.log(3 * '3');```

Error

16. What is the result of the expression 'typeof null' in JavaScript?

'object'

'null'

'undefined'

'string'

17. Which built-in method reverses the order of the elements of an array?

reverse()

invert()

backwards()

flip()

18. In JavaScript, how can you check the length of an array?

array.length()

lengthOf(array)

array.length

array.length;

19. In JavaScript, how do you initiate a loop that will continue while a condition is true?

for loop

while loop

do-while loop

if statement

20. How do you convert a string to uppercase in JavaScript?

toUpperCase()

toUpper()

upperCase()

convertToUpper()

21. Which statement is used to throw a user-defined exception in JavaScript?

throw new Error()

exception.throw()

raise new Exception()

error.throw()

22. How can you implement a private variable in JavaScript?

Using closures

Using the 'private' keyword

Declaring inside a class

Using the 'privateVar' method

23. What does the '!=='' operator signify in JavaScript?

Not equal value or not equal type

Equal value and equal type

Greater than or equal

Less than or equal

24. How do you define a function in JavaScript?

function myFunction() {}

def myFunction() {}

function = myFunction() {}

create myFunction() {}

25. What is the output of the following code? ```javascript console.log(1 + '2' + '2');```

122

Error

26. How do you call a function named 'myFunction'?

myFunction()

call myFunction()

invoke myFunction()

execute myFunction()

27. What does NaN stand for?

Not a Number

Null and None

Negative and Not

None and Not

28. What does the 'bind()' method do in JavaScript?

Binds an event to an element

Binds the value of 'this' to a specific object

Binds elements together in an array

Binds methods to a class

29. What is the difference between '==' and '===' operators in JavaScript?

'==' checks for value equality, '===' checks for both value and type equality

'==' checks for value and type equality, '===' checks for value equality

'==' and '===' are identical in functionality

None of the above

30. What is the output of the following code? ```javascript console.log(typeof NaN); ```

'number'

'NaN'

'undefined'

'string'

Moodle JavaScript MCQ Test 3