Fundamentals of Front End Development MCQs with Answers
Practice important Fundamentals of Front End Development MCQs with answers and explanations.
Chapter: 80
Q901:
Fill in the blank: To avoid bugs related to hoisting, you should always declare your variables _____
A. at the top
B. in the middle
C. after using them
D. at the bottom
Correct Answer:
A
Chapter: 80
Q902:
What will be the output of the following code?
A. 57
B. 5 7
C. 5+7
D. "Undefined"
Correct Answer:
A
Chapter: 80
Q903:
What will be the result of the following code?
A. "Undefined"
B. 10
C. Error
D. null
Correct Answer:
A
Chapter: 80
Q904:
Fill in the blank: JavaScript hoists all declarations to the _____ of the scope.
A. top
B. bottom
C. middle
D. end
Correct Answer:
A
Chapter: 80
Q905:
What will be the output of the following code?
A. 20
B. "undefined"
C. Error
D. null
Correct Answer:
B
Chapter: 80
Q906:
Fill in the blank: If a variable is declared using var, it is _____ to the top of its scope.
A. hoisted
B. ignored
C. moved
D. deferred
Correct Answer:
A
Chapter: 80
Q907:
What will the following code output?
A. 1
B. 2
C. undefined
D. Error
Correct Answer:
C
Chapter: 80
Q908:
Fill in the blank: JavaScript hoisting only applies to variables declared with _____
A. var
B. let
C. const
D. function
Correct Answer:
A
Chapter: 81
Q909:
What does the try statement do in JavaScript?
A. Tests a block of code for errors
B. Creates a custom error
C. Executes code regardless of the result
D. Handles an error
Correct Answer:
A
Chapter: 81
Q910:
Fill in the blank: The throw statement is used to create a _____ error in JavaScript.
A. custom
B. built-in
C. syntax
D. runtime
Correct Answer:
A
Chapter: 81
Q911:
What will be the output of the following code if an error occurs?
A. Error message
B. "Undefined"
C. Welcome guest!
D. Empty
Correct Answer:
A
Chapter: 81
Q912:
Fill in the blank: The finally block will always execute _____ of whether an error was thrown or not.
A. after
B. before
C. only if an error is thrown
D. only if no error is thrown
Correct Answer:
A
Chapter: 81
Q913:
What is the purpose of the throw statement?
A. To generate custom error messages
B. To handle errors
C. To test a block of code
D. To execute code regardless of the result
Correct Answer:
A
Chapter: 81
Q914:
What will the following code output if x is an empty string?
A. Input is empty
B. "empty"
C. Error
D. "Undefined"
Correct Answer:
A
Chapter: 81
Q915:
Fill in the blank: To handle multiple types of errors in JavaScript, you use the _____ statement.
A. catch
B. throw
C. finally
D. try
Correct Answer:
A
Chapter: 81
Q916:
What will the output be if x is a number less than 5?
A. Input is too low
B. too low
C. Empty
D. Error
Correct Answer:
A
Chapter: 81
Q917:
Fill in the blank: If an exception is thrown and caught, the code in the _____ block will still execute.
A. finally
B. catch
C. try
D. throw
Correct Answer:
A
Chapter: 81
Q918:
What is the result of the following code if x is undefined?
A. Input is not a number
B. "not a number"
C. Error
D. "Undefined"
Correct Answer:
A
Chapter: 81
Q919:
Fill in the blank: The catch block is used to _____ errors that occur in the try block.
A. handle
B. create
C. test
D. ignore
Correct Answer:
A
Chapter: 82
Q920:
What is the primary purpose of a debugger in JavaScript?
A. To write code more efficiently
B. To search for and diagnose errors
C. To improve code readability
D. To optimize code performance
Correct Answer:
B