Have a JavaScript interview coming up? Well, their article will prove to be really helpful to you. Have a look at the important JavaScript questions & answers asked in an interview!

Q1. What is JavaScript?

JavaScript is a lightweight, interpreted programming language with object-oriented capabilities that allows you to build interactivity into otherwise static HTML pages. The general-purpose core of the language has been embedded in Netscape, Internet Explorer, and other web browsers.

Q2. What are the data types supported by JavaScript?

The data types supported by JavaScript are:

• Undefined

• Null

• Boolean

• String

• Symbol

• Number

• Object

Q3. What are the differences between Java and JavaScript?

Java is a complete programming language. In contrast, JavaScript is a coded program that can be introduced to HTML pages. These two languages are not at all interdependent and are designed for different intents. Java is an object-oriented programming (OOPS) or structured programming language like C++ or C, whereas JavaScript is a client-side scripting language.

Q4. Which is faster between JavaScript and an ASP script?

JavaScript is faster. JavaScript is a client-side language,, and thus it does not need the assistance of the webserver to execute. On the other hand, ASP is a server-side language and hence is always slower than JavaScript. Javascript now is also a server-side language (nodejs).

Q5. What is the difference between JavaScript and JScript?

Netscape provided the JavaScript language. Microsoft changed the name and called it JScript to avoid the trademark issue. In other words, you can say JScript is the same as JavaScript, but Microsoft provides it.

Q6. What is DOM? What is the use of document objects?

DOM stands for Document Object Model. A document object represents the HTML document. It can be used to access and change the content of HTML.

Q7. Difference between Client-side JavaScript and Server-side JavaScript?

Client-side JavaScript comprises the basic language and predefined objects which are relevant to running JavaScript in a browser. The client-side JavaScript is embedded directly in the HTML pages. The browser interprets this script at runtime.

Server-side JavaScript also resembles client-side JavaScript. It has relevant JavaScript that is to run on a server. The server-side JavaScript is deployed only after compilation.

Q8. What is the 'this' keyword in JavaScript?

'This' keyword refers to the object from where it was called.

Q9. What is a prompt box?

A prompt box is a box that allows the user to enter input by providing a text box. A label and box will be provided to enter the text or number.

Q10. What is the real name of JavaScript?

The original name was Mocha, a name chosen by Marc Andreessen, founder of Netscape. In September of 1995, the name was changed to LiveScript. In December 1995, after receiving a trademark license from Sun, the name JavaScript was adopted.