JavaScript MCQ Quiz - Objective Question with Answer for JavaScript - Download Free PDF

The correct answer is option 3.

Concept:

• In JavaScript "= = =" operator defines Is identical (is equal to and is of the same type). 
• The === operator in javascript compares the equality of two operands with type.
• If both type and value are equal, the condition is true; otherwise, it is false. 
• In javascript, the equality operator is used to check if two values are equal. In javascript, the comparison is done with the == and === operators.
• The fundamental difference between the == and === operators in javascript is that the == operator converts the operands' types before comparing them, whereas the === operator compares the operands' values as well as their data types.
• The type conversion of the operand is the major difference between == and === in Javascript.

Syntax for equality:

x === y

Example:

let a = 10;

let b = '10';

let c = 10;

console.log(a===b); //output: false;

console.log(a===c); //output: true;

Syntax for equality:

x == y

Example:

let a = 10;

let b = '10';

let c = 10;

console.log(a===b); //output: true;

console.log(a===c); //output: true;

Hence the correct answer Is identical (is equal to and is of the same type).

Concept:

Division of any integer by zero is not an error in the JavaScript. It just prints the infinity as a result. However, there is an exception in JavaScript, dividing zero with zero will not have any defined number/value so, the result of this specific operation is a special value "Not a Number" (or NaN) and printed as NaN.

Answer: Option 2

Concept:

• The JavaScript Programming language came into existence in 1995.
• JavaScript is a programming language used in web development.
• It was developed by Netscape to add dynamic and interactive elements to websites. 
• JavaScript is influenced by Java.
• It is a client-side scripting language.
• A JavaScript code can be inserted anywhere within the HTML of a webpage.
• JavaScript is a scripting language that is used to develop websites.
• JavaScript helps to add functionality and behaviors to your website, allowing your website’s visitors to interact with content in many imaginative ways.
• In September 1995, a Netscape programmer named Brandan Eich developed a new scripting language in just 10 days.
• It was originally named Mocha, but quickly became known as LiveScript and, later, JavaScript.

Explanation:

The Behaviour Of Operator “+” in JavaScript:

If any of the operands is a string, all others are converted to a string, and concatenation is done, otherwise, arithmetic addition is done.

for example if the var x =  16+ "Volvo"+ 4; is given then output will be 16Volvo4.

Answer: Option 3

Concept:

• The write() method writes HTML expressions or JavaScript code to a document
• In Javascript, document.write(" ") at client side and response.write on server side

​Additional Information

innerHTML: 

This property used to return/set the content of any HTML element.

console.log(): 

This method is used to write output to the browser's console.

This is generally used while testing the web application.

window.alert(): 

This method is used to display a dialog box to the user to alert the user about something.

An alert dialog box is mostly used to give a warning message to the users. 
for example, an input field requires to enter some text but the user does not enter that field then as a part of validation we can use alert box to give warning message.

Answer: Option 3

Explanation:

Option 1: < Div > and < / Div >

This is not correct. as this pair used to create a division in an HTML page/document. 

Option 2: < Body > and < / Body >

This is not correct. as body tag used to define the body of HTML page.

Option 3: ​