Javascript Functions MCQ - Quiz

Q: To show the text with a scrolling effect, which of the following HTML tags is used?

A. <pre class = "prettyprint"><xmp> <marquee> </xmp></pre>
B. <pre class = "prettyprint"><xmp> <scroll> </xmp></pre>
C. <pre class = "prettyprint"><xmp> <div> </xmp></pre>
D. None of the bove

Correct Option: A
Remarks:

Explanation:


The <marquee> tag is used to create a scrolling text or image in HTML. It was first introduced in Internet Explorer and was later adopted by other web browsers. 
However, it is considered a non-standard element and its use is not recommended because it can create accessibility issues and is not supported by all web browsers. 
It is better to use alternative methods to create scrolling content, such as using CSS or JavaScript.

The <marquee> tag is a non-standard HTML element that is used to scroll a text or image either horizontally or vertically. 
In simple words, we can say that it automatically scrolls the image or text in up, down, left, and right direction.

Q: Which of the below number object functions gives the number's value back?

A. toString()
B. valueOf()
C. toLocaleString()
D. toPrecision()

Correct Option: B
Remarks:

Explanation:

valueOf() is a method that is available on many JavaScript objects, and it returns the primitive value of the object.
For example, if you have a number object x that was created using the Number constructor,
you can use the valueOf() method to get the primitive value of x.
Here's an example:
let x = new Number(5); console.log(x.valueOf()); // Output: 5

Q: What does the `Math.random()` function return in JavaScript?

A. A random integer between 0 and 1
B. A random float between 0 and 1
C. A random float between -1 and 1
D. None of these

Correct Option: B
Remarks:

Explanation:

The Math.random() function returns a random float between 0 and 1.
The Math.random() function returns a random float between 0 and 1 because this is the range of values that the function is designed to return.
The function uses a pseudo-random number generator to generate the random float, which means that the numbers it generates are not truly random, but they are good enough for most purposes.
The Math.random() function is often used to generate random numbers for things like games, simulations, and other applications where a truly random number is not required.

Q: What does the split() function do in JavaScript?

A. Splits a string into an array of substrings
B. Joins the elements of an array into a string
C. Removes whitespace from a string
D. None of these

Correct Option: A
Remarks:

Explanation:

The split() function splits a string into an array of substrings based on a specified delimiter.
The delimiter can be a character, a string, or a regular expression.

Q: What does the `sort()` function do in JavaScript?

A. Sorts the elements of an array in ascending order
B. Sorts the elements of an array in descending order
C. Sorts the elements of an array in random order
D. None of these

Correct Option: A
Remarks:

Explanation:

The sort() function sorts the elements of an array in ascending order.
By default, it compares the elements as strings.
You can pass a comparison function as an argument to sort the elements in a different way.

Q: What does the `isFinite()` function do in JavaScript?

A. Checks if a value is a finite number
B. Checks if a value is infinite
C. Checks if a value is not a number
D. None of these

Correct Option: A
Remarks:

Explanation:

The isFinite() function checks if a value is a finite number.
It returns true if the value is a finite number, and false if it is not.

Q: What is a higher-order function in JavaScript?

A. A function that returns another function
B. A function that takes another function as an argument
C. A function that does both of the above
D. none of these

Correct Option: C
Remarks:

Explanation:

A higher-order function is a function that either returns another function or takes another function as an argument, or both.
Higher-order functions are a powerful tool in functional programming because they allow you to create new functions by combining and modifying existing ones.

Q: What does the following function do in JavaScript?

function isPalindrome(str) {
str = str.toLowerCase();
return str === str.split('').reverse().join('');
}

A. calculates the area of a circle
B. converts a string to uppercase
C. checks if a string is a palindrome
D. sorts an array in ascending order

Correct Option: C
Remarks:

Explanation:

This function takes in a single argument, str, and uses the toLowerCase() method to convert the string to lowercase.
It then uses the split(), reverse(), and join() methods to check if the string is a palindrome (i.e., it reads the same forwards and backwards).

Q: What does the this keyword refer to in the following code?

const user = {
name: 'John',
greet: () => {
console.log('Hello, ' + this.name + '!');
}
}

user.greet();

A. the global object
B. the function itself
C. the object that the function is a property of
D. the object that the function is called on

Correct Option: A
Remarks:

Explanation:

In this case, the greet function is an arrow function, which means that the this keyword is not dynamically bound to the object that the function is called on.
Instead, it refers to the value of this in the surrounding context, which in this case is the global object.

Q: What is the result of the following function call in JavaScript?

add(10, 5);

function add(x, y) {
return x + y;
}

A. 15
B. '105'
C. undefined
D. TypeError

Correct Option: A
Remarks:

Explanation:

In this case, the add function is defined before it is called, so the function call is successful and returns the sum of the two numbers, 15.

Javascript Functions MCQ - Quiz

Question: To show the text with a scrolling effect, which of the following HTML tags is used?

Question: Which of the below number object functions gives the number's value back?

Question: What does the `Math.random()` function return in JavaScript?

Question: What does the split() function do in JavaScript?

Question: What does the `sort()` function do in JavaScript?

Question: What does the `isFinite()` function do in JavaScript?

Question: What is a higher-order function in JavaScript?

Question: What does the following function do in JavaScript?
function isPalindrome(str) { str = str.toLowerCase(); return str === str.split('').reverse().join(''); }

Question: What does the this keyword refer to in the following code?
const user = { name: 'John', greet: () => { console.log('Hello, ' + this.name + '!'); } } user.greet();

Question: What is the result of the following function call in JavaScript?
add(10, 5); function add(x, y) { return x + y; }

Javascript Functions MCQ - Quiz

Question: To show the text with a scrolling effect, which of the following HTML tags is used?

Question: Which of the below number object functions gives the number's value back?

Question: What does the Math.random() function return in JavaScript?

Question: What does the split() function do in JavaScript?

Question: What does the sort() function do in JavaScript?

Question: What does the isFinite() function do in JavaScript?

Question: What is a higher-order function in JavaScript?

Question: What does the following function do in JavaScript? function isPalindrome(str) { str = str.toLowerCase(); return str === str.split('').reverse().join(''); }

Question: What does the this keyword refer to in the following code? const user = { name: 'John', greet: () => { console.log('Hello, ' + this.name + '!'); } } user.greet();

Question: What is the result of the following function call in JavaScript? add(10, 5); function add(x, y) { return x + y; }

Question: What does the `Math.random()` function return in JavaScript?

Question: What does the `sort()` function do in JavaScript?

Question: What does the `isFinite()` function do in JavaScript?

Question: What does the following function do in JavaScript?
function isPalindrome(str) { str = str.toLowerCase(); return str === str.split('').reverse().join(''); }

Question: What does the this keyword refer to in the following code?
const user = { name: 'John', greet: () => { console.log('Hello, ' + this.name + '!'); } } user.greet();

Question: What is the result of the following function call in JavaScript?
add(10, 5); function add(x, y) { return x + y; }