JavaScript Basics Quiz
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Question 1/15
Which operator is used to assign a value to a variable?
Select your answer
Question 2/15
What will the following code output?
var fruits = ['Apple', 'Banana', 'Mango'];
console.log(fruits[1]);
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Question 3/15
What does the "alert()" function do in JavaScript?
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Question 4/15
Which method can be used to convert a JSON string into a JavaScript object?
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Question 5/15
What does "const" declare in JavaScript?
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Question 6/15
How do you find the number with the highest value of x and y?
Math.max(x, y);
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Question 7/15
What does "NaN" stand for in JavaScript?
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Question 8/15
Which of these is not a reserved word in JavaScript?
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Question 9/15
When the following code is executed, what will the value of the expression be?
3 == '3'
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Question 10/15
What is the output when you execute the following code?
console.log(typeof 42);
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Question 11/15
Which of the following will write "Hello World!" to the console?
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Question 12/15
Which of the following is a string method in JavaScript?
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Question 13/15
How do you round 7.25 to the nearest integer in JavaScript?
Math.round(7.25);
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Question 14/15
What is the output of the following JavaScript code?
var x = 10;
x += 5;
console.log(x);
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Question 15/15
What will the following expression return: Boolean(0);
Boolean(0);
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Your Results
You did not answer any questions correctly.
Your Answers
Question 1/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
Which operator is used to assign a value to a variable?
Available answers
The assignment operator in JavaScript is
=
, used to assign values to variables.
Question 2/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What will the following code output?
var fruits = ['Apple', 'Banana', 'Mango'];
console.log(fruits[1]);
Available answers
Arrays in JavaScript are zero-indexed, so
fruits[1]
contains 'Banana'
.
Question 3/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What does the "alert()" function do in JavaScript?
Available answers
The
alert()
function displays an alert box containing a specified message and an OK button.
Question 4/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
Which method can be used to convert a JSON string into a JavaScript object?
Available answers
The
JSON.parse()
method is used to convert a JSON string into a JavaScript object.
Question 5/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What does "const" declare in JavaScript?
Available answers
const
declares a variable that is read-only after initialization, meaning it cannot be reassigned.
Question 6/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
How do you find the number with the highest value of x and y?
Math.max(x, y);
Available answers
The function
Math.max()
is used to find the highest value among its parameters.
Question 7/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What does "NaN" stand for in JavaScript?
Available answers
NaN
stands for "Not-a-Number", indicating a value that is not a legal number.
Question 8/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
Which of these is not a reserved word in JavaScript?
Available answers
The word
program
is not a reserved keyword in JavaScript, unlike switch, throw, default
.
Question 9/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
When the following code is executed, what will the value of the expression be?
3 == '3'
Available answers
The
==
operator checks for equality with type coercion. Hence 3 == '3'
is true
.
Question 10/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What is the output when you execute the following code?
console.log(typeof 42);
Available answers
The
typeof
operator returns 'number'
for numerical literals like 42
.
Question 11/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
Which of the following will write "Hello World!" to the console?
Available answers
The function
console.log()
is used to output messages to the web console in JavaScript.
Question 12/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
Which of the following is a string method in JavaScript?
Available answers
The
toUpperCase()
method converts a string to uppercase letters.
Question 13/15
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answer was correct
🙁 Your
answer was incorrect
How do you round 7.25 to the nearest integer in JavaScript?
Math.round(7.25);
Available answers
To round a number in JavaScript, use
Math.round()
.
Question 14/15
😊 Your
answer was correct
🙁 Your
answer was incorrect
What is the output of the following JavaScript code?
var x = 10;
x += 5;
console.log(x);
Available answers
The code uses
+=
to add 5
to x
, giving 15
.
Question 15/15
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answer was correct
🙁 Your
answer was incorrect
What will the following expression return: Boolean(0);
Boolean(0);
Available answers
The expression
Boolean(0)
returns false
because 0
is considered a "falsy" value in JavaScript.