Fundamentals of Front End Development MCQs with Answers
Practice important Fundamentals of Front End Development MCQs with answers and explanations.
Chapter: 55
Q641:
Fill in the blank: The primary reason for using comments in code is to ___ the code to others.
A. Obfuscate
B. Hide
C. Explain
D. Ignore
Correct Answer:
C
Chapter: 56
Q642:
What is the purpose of variables in JavaScript?
A. To store data values
B. To create functions
C. To style HTML elements
D. To manage events
Correct Answer:
A
Chapter: 56
Q643:
Which of the following is a valid variable declaration in JavaScript?
A. var 1x;
B. var x1;
C. var #x;
D. var x_1;
Correct Answer:
B
Chapter: 56
Q644:
What does the following code do: var x = 5; var y = 6; var z = x + y;
A. Assigns 5 to y
B. Assigns the sum of x and y to z
C. Assigns 11 to y
D. Assigns 6 to z
Correct Answer:
B
Chapter: 56
Q645:
Which of the following is NOT a valid JavaScript identifier?
A. _myVar
B. 2ndVar
C. $amount
D. myVar_2
Correct Answer:
B
Chapter: 56
Q646:
Fill in the blank: In JavaScript, the equal sign (=) is an ___ operator.
A. equal to
B. assignment
C. comparison
D. arithmetic
Correct Answer:
B
Chapter: 56
Q647:
What will be the output of the following code: var x = 5; var y = "5" + 5; var z = "Hello" + 5;?
A. x=5, y=55, z=Hello5
B. x=5, y=10, z=Hello5
C. x=5, y=10, z=5Hello
D. x=5, y=55, z=5Hello
Correct Answer:
A
Chapter: 56
Q648:
How can multiple variables be declared in one statement in JavaScript?
A. Using var followed by each variable, separated by commas
B. Using let for each variable
C. Using var for each variable on new lines
D. Using commas alone
Correct Answer:
A
Chapter: 56
Q649:
What does the following code do? var txt1 = "What a very "; txt1 += "nice day";
A. Adds the text "nice day" to txt1
B. Subtracts "nice day" from txt1
C. Multiplies txt1 by "nice day"
D. Divides txt1 by "nice day"
Correct Answer:
A
Chapter: 56
Q650:
Fill in the blank: In JavaScript, numbers are written without ___.
A. commas
B. quotes
C. spaces
D. semicolons
Correct Answer:
B
Chapter: 56
Q651:
What is the result of var x = 5 + 2 + 3; in JavaScript?
A. 10
B. 52
C. 7
D. undefined
Correct Answer:
A
Chapter: 56
Q652:
Which operator is used in JavaScript to concatenate strings?
A. -
B. *
C. +
D. /
Correct Answer:
C
Chapter: 56
Q653:
What will be the value of z after executing the code var x = 5; var y = 2; var z = x + y;?
A. 2
B. 7
C. 5
D. 3
Correct Answer:
B
Chapter: 56
Q654:
Fill in the blank: JavaScript strings are written inside ___.
A. curly braces
B. quotes
C. square brackets
D. parentheses
Correct Answer:
B
Chapter: 56
Q655:
Which of the following is an example of adding a number to a string in JavaScript?
A. var x = 5 + "5";
B. var y = "5" - 5;
C. var z = "5" * 5;
D. var w = "5" / 5;
Correct Answer:
A
Chapter: 56
Q656:
What is the output of the following code: var pi = 3.14; var answer = "Yes I am!"; var anum = '3.14';?
A. pi=3.14, answer="Yes I am!", anum='3.14'
B. pi=3.14, answer=Yes, anum=3.14
C. pi=3, answer="Yes I am!", anum=3.14
D. undefined for all
Correct Answer:
A
Chapter: 56
Q657:
Fill in the blank: JavaScript variables must begin with a letter, ____, or ____.
A. digit, underscore
B. underscore, dollar sign
C. dollar sign, digit
D. digit, period
Correct Answer:
B
Chapter: 56
Q658:
What will be the value of txt3 after the following code: txt1 = "John"; txt2 = "Doe"; txt3 = txt1 + " " + txt2;
A. JohnDoe
B. DoeJohn
C. John Doe
D. Doe John
Correct Answer:
C
Chapter: 57
Q659:
What keyword is used to define a function in JavaScript?
A. func
B. define
C. function
D. method
Correct Answer:
C
Chapter: 57
Q660:
Which of the following is a correct JavaScript function declaration?
A. function myFunction() { }
B. func myFunction() { }
C. function myFunction { }
D. myFunction() { }
Correct Answer:
A