Fundamentals of Front End Development MCQs with Answers
Practice important Fundamentals of Front End Development MCQs with answers and explanations.
Chapter: 54
Q621:
What is the recommended maximum length for a line of JavaScript code for best readability?
A. 60 characters
B. 80 characters
C. 100 characters
D. 120 characters
Correct Answer:
B
Chapter: 54
Q622:
Where is the best place to break a long JavaScript statement?
A. After a keyword
B. After a variable
C. After an operator
D. After a semicolon
Correct Answer:
C
Chapter: 54
Q623:
What is the purpose of code blocks in JavaScript?
A. To group statements to be executed together
B. To declare variables
C. To define functions
D. To write comments
Correct Answer:
A
Chapter: 54
Q624:
How are code blocks defined in JavaScript?
A. Using square brackets []
B. Using parentheses ()
C. Using curly brackets {}
D. Using angle brackets <>
Correct Answer:
C
Chapter: 54
Q625:
Fill in the blank: In JavaScript, the ___ character is used to separate statements on the same line.
A. Colon
B. Semicolon
C. Comma
D. Period
Correct Answer:
B
Chapter: 54
Q626:
What happens if you forget to add a semicolon at the end of a JavaScript statement?
A. The code will not run
B. The next statement will be ignored
C. JavaScript will add it automatically
D. The code will throw an error
Correct Answer:
C
Chapter: 54
Q627:
What is the significance of the following code: a = 5; b = 6; c = a + b;
A. It defines a function
B. It declares a variable
C. It declares multiple variables
D. It assigns and computes values
Correct Answer:
D
Chapter: 54
Q628:
Fill in the blank: JavaScript statements are often grouped together in ___ to be executed together.
A. Functions
B. Loops
C. Code blocks
D. Arrays
Correct Answer:
C
Chapter: 55
Q629:
What is the primary purpose of comments in JavaScript?
A. To speed up execution
B. To explain and make the code more readable
C. To make code difficult to read
D. To execute code faster
Correct Answer:
B
Chapter: 55
Q630:
Which symbol is used to start a single-line comment in JavaScript?
A. //
B. /*
C. <!--
D. ##
Correct Answer:
A
Chapter: 55
Q631:
How do you start a multi-line comment in JavaScript?
A. //
B. /*
C. <!--
D. #
Correct Answer:
B
Chapter: 55
Q632:
What happens to the code within a comment block in JavaScript?
A. It is executed twice
B. It is ignored and not executed
C. It is executed normally
D. It is stored for later execution
Correct Answer:
B
Chapter: 55
Q633:
How do you end a multi-line comment in JavaScript?
A. //
B. */
C. -->
D. ##
Correct Answer:
B
Chapter: 55
Q634:
What is the benefit of using comments to prevent code execution?
A. It improves performance
B. It allows for testing alternative code
C. It changes the output
D. It reduces code size
Correct Answer:
B
Chapter: 55
Q635:
Fill in the blank: In JavaScript, single-line comments start with ___ and extend to the end of the line.
A. /*
B. //
C. <!--
D. ##
Correct Answer:
B
Chapter: 55
Q636:
Fill in the blank: In JavaScript, multi-line comments start with ___ and end with ___.
A. //, //
B. <!--, -->
C. /*, */
D. ##, ##
Correct Answer:
C
Chapter: 55
Q637:
What is the outcome of the following code? // var x = 5;
A. The value of x is set to 5
B. The code is ignored and not executed
C. The code throws an error
D. The value of x is set to 0
Correct Answer:
B
Chapter: 55
Q638:
Fill in the blank: JavaScript comments are useful for making the code ___.
A. Slower
B. Easier to understand
C. More complex
D. More efficient
Correct Answer:
B
Chapter: 55
Q639:
Which of the following is NOT a valid comment style in JavaScript?
A. // This is a comment
B. <!-- This is a comment -->
C. /* This is a comment */
D. ## This is a comment
Correct Answer:
D
Chapter: 55
Q640:
What does the following code do? /* This is a multi-line comment */
A. Executes the code inside the comment
B. Throws an error
C. Ignores the code inside the comment
D. Runs the code twice
Correct Answer:
C