Technical interview questions and answers are extremely important for JavaScript Interviews because JavaScript powers most modern web applications. Companies evaluate your understanding of functions, scope, closures, events, DOM manipulation, ES6 features, promises, async/await, and real-time coding skills. JavaScript is one of the most commonly tested subjects in frontend developer interviews, full-stack roles, and placement assessments. Companies like TCS, Infosys, Wipro, Cognizant, and Accenture frequently include JavaScript questions in their technical rounds. This guide covers the most frequently asked JavaScript interview questions with detailed explanations to help freshers and job seekers prepare effectively. Learning these questions will give you confidence during coding tests, practical tasks, and web development interviews.
Frontend developers should enhance their skills by mastering CSS styling techniques and HTML structure fundamentals
Showing 10 of 78 questions
11. whats a way to append a value to an array?
arr[arr.length] = value;
12. What is this keyword?
It refers to the current object.
13. What is the main difference between Client side JavaScript and and Server side Java Script. How actually they run on both side with Example?
Clientside Javascript encompasses the core language plus extras such as the predefined objects, only relevant to running Javasript in a browser.The clientside javascript is embedded directly in the HTML pages and is interpreted by the browser completly at the run time. Serverside javascript also encompasses the core language plus extas as the predefined objects and functions only relevant to running Javasript in a server.The serverside javascripts are compiled before they are deployed.
14. What is JavaScript?
JavaScript is a general-purpose programming language designed to let programmers of all skill levels control the behavior of software objects. The language is used most widely today in Web browsers whose software objects tend to represent a variety of HTML elements in a document and the document itself. But the language can be--and is--used with other kinds of objects in other environments. For example, Adobe Acrobat Forms uses JavaScript as its underlying scripting language to glue together obj
15. What is JavaScript?
JavaScript is a platform-independent,event-driven, interpreted client-side scripting and programming language developed by Netscape Communications Corp. and Sun Microsystems.
16. whats relationship between JavaScript and ECMAScript?
ECMAScript is yet another name for JavaScript (other names include LiveScript). The current JavaScript that you see supported in browsers is ECMAScript revision 3.
17. How do you submit a form using Javascript?
Use document.forms[0].submit();
(0 refers to the index of the form if you have more than one form in a page, then the first one has the index 0, second has index 1 and so on).
18. How to detect the operating system on the client machine?
In order to detect the operating system on the client machine, the navigator.appVersion
string (property) should be used
19. How do you target a specific frame from a hyperlink?
Include the name of the frame in the target attribute of the hyperlink. >My Page
20. Where are cookies actually stored on the hard disk?
This depends on the user's browser and OS.
In the case of Netscape with Windows OS,all the cookies are stored in a single file called
cookies.txt
c:\Program Files\Netscape\Users\username\cookies.txt
In the case of IE,each cookie is stored in a separate file namely username@website.txt.
c:\Windows\Cookies\username@Website.txt