Javascript Interview Questions and Answers in 2025 (100+ Q&A)

Javascript

Ques:- what difference between args.length and args.length() in command line argument?

Asked In :- Mobio Solutions, ShopKeeper, KFT, Vuram, Chili Piper, lam research, einfochips, the aa, qburst, lightspeed hq,

Right Answer:
`args.length` is used to get the number of command line arguments passed to a Java program, while `args.length()` is incorrect because `length` is a property, not a method.

Javascript

Ques:- coding of java scripts

Asked In :- Twilio, XorLabs, ITRS Group, Zysk Technologies, Softserve Global, stefanini it solutions, ionidea, evon technologies, heroku, aspire global,

Right Answer:
To code in JavaScript, you can use the following basic structure:

```javascript
// This is a simple JavaScript function
function greet(name) {
return "Hello, " + name + "!";
}

// Call the function
console.log(greet("World")); // Output: Hello, World!
```

Javascript

Ques:- what is a dataset

Asked In :- Incise Infotech, INNOART TECHNOLOGIES, Zessta Software Services, KareXpert Technologies, ITRS Group, APPS Team Technologies, Emipro Technologies, Pactera Technologies India, Thinkitive Technologies, Reliance Jio,

Right Answer:
A dataset is a collection of related data, typically organized in a structured format, such as tables, that can be used for analysis or processing in programming and data manipulation.

Javascript

Ques:- java is pure object oriented or not?

Asked In :- rapidera technologies, AgilePoint Software India, EY GDS, BluePi, MindBowser Info Solutions, Adloid, etsy, canonical ltd., balsamiq, Trinamix Systems,

Right Answer:
Java is not considered a pure object-oriented language because it supports primitive data types (like int, char, etc.) that are not objects.

Comments

Admin May 17, 2020

Yes, Java is completely object oriented...! OOPS principle says that data should control the code that in java happens, while in procedural languages code control the data.
Even the primitive datatypes in java like int are represented in object, see wrapper classes.
Finally its follow, all OOPS principal, like Encapsulation, Polymorphism and Inheritance.

Admin May 17, 2020

Yes, Java is completely object oriented..
Because data should control the code...
Finally all oops principal, Like Encapsulation, polymorphism, Data Abstraction and Inheritance

Javascript

Ques:- what is the different between html and java?why the java is required in internet?

Asked In :- Thirdware, Beautiful Code, quest global, vistaprint, mmt digital, softwire, dws, knowledge lens, nextwave multimedia, tradebyte software gmbh,

Right Answer:
HTML (HyperText Markup Language) is a markup language used to create the structure and content of web pages, while Java is a programming language used to create dynamic and interactive applications. Java is required on the internet for building complex web applications, server-side processing, and enabling features like user interactivity and data manipulation.

Javascript

Ques:- how to get no of items from from weblist?

Asked In :- Abzooba India Infotech, Gloify, ADVERB, Ennea, edgeverve, apptio, nintex, adam milo, webandcrafts, tsi,

Right Answer:
You can get the number of items from a web list (like a `<select>` element) in JavaScript using the following code:

```javascript
const webList = document.getElementById('yourSelectElementId'); // Replace with your select element's ID
const numberOfItems = webList.options.length;
```

Javascript

Ques:- how to use java script

Asked In :- Maventic, OIP, Prodapt SA, redBus India, Terralogic, Whatfix, 159 Solutions, Roanuz, alight solutions, bigcommerce,

Right Answer:
To use JavaScript, you can include it in your HTML file by placing it within `<script>` tags. You can write your JavaScript code directly in the HTML file or link to an external JavaScript file using the `src` attribute. For example:

```html
<!DOCTYPE html>
<html>
<head>
<title>My Page</title>
</head>
<body>
<h1>Hello, World!</h1>
<script>
console.log('This is JavaScript code running!');
</script>

<script src="script.js"></script>
</body>
</html>
```

Javascript

Ques:- What’s Prototypes for JavaScript

Asked In :- QuickXpert Infotech, CodeClouds IT Solutions, Mobio Solutions, Zenon, AMI Tech India, Netcon Technologies, Viral Technologies, greenway health, impetus, dude solutions,

Javascript

Ques:- Explain the steps for connecting the system to Internet.

Asked In :- Hidden Brains InfoTech, Webvillee Technology, Zyoin Web Pvt., Bristlecone India, GyanMatrix Technologies, Invenger Technologies, ATYETI, EPO, Vuram, aditi technologies,

Right Answer:
1. Ensure you have an internet service provider (ISP).
2. Connect your modem to a power source and to the phone line or cable outlet.
3. Connect your router to the modem using an Ethernet cable (if using a separate router).
4. Power on the router.
5. Connect your device (computer, smartphone, etc.) to the router via Ethernet cable or Wi-Fi.
6. Configure network settings on your device if necessary.
7. Open a web browser and test the connection by visiting a website.

Javascript

Ques:- Write a program in Java to display the IP address of the local and remote machine.

Asked In :- Digite Infotech, Codemind Staffing Solutions, ISC Software, Globant India, DSK Digital Technologies, Coforge, william hill, vee technologies, bairesdev, sportskeeda,

Right Answer:
```java
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPAddressDisplay {
public static void main(String[] args) {
try {
// Display local IP address
InetAddress localHost = InetAddress.getLocalHost();
System.out.println("Local IP Address: " + localHost.getHostAddress());

// Display remote IP address (example: google.com)
InetAddress remoteHost = InetAddress.getByName("google.com");
System.out.println("Remote IP Address: " + remoteHost.getHostAddress());
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
}
```

Javascript

Ques:- Are there any training Institutions on iphone Automation testing?

Asked In :- KRIOS Info Solutions, Fission Infotech, Terralogic, Digital Harbor, Tyto Software, ITH Technologies (Infotech HUB), Ennea, Orion Innovation, ncs group, yondu, inc.,

Right Answer:
Yes, there are several training institutions that offer courses on iPhone automation testing, including online platforms like Udemy, Coursera, and specialized training centers.

Javascript

Ques:- how to run the servlet in tomcat

Asked In :- AHEX TECHNOLOGIES, HashRoot Technologies, Digite Infotech, Prodapt SA, Canopus Infosystems, OneOrigin, Digital Mesh Softech, Silicon Stack, VibrantMinds Technologies, Rumango,

Right Answer:
To run a servlet in Tomcat, follow these steps:

1. **Install Tomcat**: Download and install Apache Tomcat on your machine.

2. **Create a Web Application Directory**: Inside the `webapps` folder of your Tomcat installation, create a new directory for your web application (e.g., `myapp`).

3. **Create a `WEB-INF` Directory**: Inside your application directory, create a `WEB-INF` folder.

4. **Create `web.xml`**: Inside the `WEB-INF` folder, create a `web.xml` file to configure your servlet. Define your servlet and its mapping in this file.

5. **Compile Your Servlet**: Write your servlet code in Java, compile it, and place the resulting `.class` files in a `classes` folder inside `WEB-INF`.

6. **Start Tomcat**: Run the `startup.bat` (Windows) or `startup.sh` (Linux/Mac)

Javascript

Ques:- show the date in textbox when we select item (items like– today,yesterday,lastweek,lastmonth,lastyear) from dropdownlist using javascript?

Asked In :- Shipmnts, ScriptsHub Technologies, 3clogic, TAO Solutions, Emipro Technologies, farfetch, intrasoft international, poshmark, object edge, hotwax systems,

Comments

Admin May 17, 2020

<select id="dayType" name="dayType" onchange="showFields()">
<option>Today</option>
<option>Yesterday</option>
<option>Last Week</option>
<option>Last Month</option>
<option>Voucher Number</option>
</select>
<input type="text" id="dateValue" name="dateValue">
<script type="text/javascript">
function showFields()
{
if(jQuery('#dayType').val()=='Today' ||
jQuery('#dayType').val()=='Yesterday')
{
jQuery('#dateValue').datepicker({changemonth:
true, changeyear: true, dateformat:'mm/dd/yy'});
}else jQuery('#dateValue').datepicker('destroy');
}
</script>

Javascript

Ques:- Are there any iphone Institutes which also train iphone automation testing in Hyderabad?

Asked In :- BillDesk, Befree, Surya Software, JustDial, BluePi, AM InfoWeb, Forsys, AcuityAds, ConveGenius, Pivox Labs,

Right Answer:
Yes, there are several institutes in Hyderabad that offer training in iPhone automation testing. You can check local training centers or online platforms for specific courses.

Javascript

Ques:- Some XYZ company is arranging for online aptitude tests. Draw detailed E-R diagram for the same..

Asked In :- Zentron Labs, Aruba Networks, Zenon, Juego Studio, ApMoSys Technologies, Symphony Technologies, Neo Code, sse, confiz, urjanet,

Right Answer:
To create an E-R diagram for an online aptitude test system, you can include the following entities and relationships:

1. **Entities:**
- **User**
- Attributes: UserID (PK), Name, Email, Password, Role (Admin/User)
- **Test**
- Attributes: TestID (PK), Title, Description, Duration, TotalMarks
- **Question**
- Attributes: QuestionID (PK), TestID (FK), QuestionText, OptionA, OptionB, OptionC, OptionD, CorrectAnswer
- **Response**
- Attributes: ResponseID (PK), UserID (FK), TestID (FK), QuestionID (FK), SelectedOption, MarksObtained
- **Result**
- Attributes: ResultID (PK), UserID (FK), TestID (FK), TotalMarks, Score, DateTaken

2. **Relationships:**
- User can take multiple Tests (1 to Many)

Javascript

Ques:- how many feet does a centipeed have?

Asked In :- Sarvaha Systems, Streebo Solutions, Abzooba India Infotech, iProgrammer, VEDA IIT, MRI Software, VYSHNAVI INFORMATION TECHNOLOGIES INDIA, Neoito, Aegan Technologies, ocado technology,

Right Answer:
A centipede can have anywhere from 30 to 354 legs, depending on the species.

Javascript

Ques:- what is interface ?

Asked In :- Addweb solutions, Acquia Inc., e2e, Aptos, Synapse Labs, KUB, SightSpectrum Technology Solutions (P), knowit, heartland dental, omc,

Right Answer:
In JavaScript, an interface is a defined structure that specifies a contract for objects, outlining the methods and properties they must implement, but it does not provide the actual implementation. JavaScript does not have built-in support for interfaces like some other languages, but you can simulate them using conventions or TypeScript.

Comments

Admin May 17, 2020

interface having all abstract methods and doesnt have imp;ementation

Admin May 17, 2020

interface has only declaration part only not definition part
is not there,

Javascript

Ques:- what is onfocus and onblur events in java script?

Asked In :- toobler technologies, City Union Bank, AppSquadz, Invenger Technologies, Kireeti Soft Technologies, 7EDGE, ToggleNow, Codesmith, Evergent Technologies, Infinity Works Consulting,

Right Answer:
The `onfocus` event occurs when an element, such as an input field, gains focus (usually when clicked or tabbed into), while the `onblur` event occurs when that element loses focus (when clicked away or tabbed out).

Comments

Admin May 17, 2020

The onfocus event occurs when an object gets focus.
The onblur event occurs when an object loses focus.

Admin May 17, 2020

onFocus : occurs when an element gets focus
onBlur : occurs when an element loses focus

Javascript

Ques:- whether javascript runs on client side or server-side?

Asked In :- Zessta Software Services, Amiti Software Technologies, ATYETI, PredictiveHire, KUB, Infinity Works Consulting, Bounteous, quest global, paysafe group, worldline global,

Right Answer:
JavaScript can run on both client-side and server-side.

Comments

Admin May 17, 2020

client side

Admin May 17, 2020

javascript is run on client side.doing client side validation.

Javascript

Ques:- can wwe trace a java program (class)

Asked In :- Zen Corp Techno Solutions, Galaxy Weblinks, Isoft Software Technologies, Exalca Technologies, DePronto Infotech, Neo Code, cloudbees, wp engine, razorpay, catalyte,

Right Answer:
No, we cannot trace a Java program (class) directly in JavaScript. Java and JavaScript are different languages and run in different environments.

The JavaScript category on takluu.com is crafted for aspiring web developers, front-end engineers, and full-stack professionals who want to ace JavaScript-related interviews. As one of the core technologies of the web (along with HTML and CSS), JavaScript enables the creation of responsive, user-friendly, and interactive websites.

In this category, you’ll explore fundamental and advanced JavaScript concepts including variables, data types, loops, functions, events, arrays, objects, and more. It also covers essential topics such as DOM manipulation, event handling, closures, promises, async/await, ES6+ features, and error handling.

You’ll also learn about JavaScript’s execution context, scope chain, hoisting, prototypal inheritance, and the event loop, which are frequently asked in technical interviews. Understanding these concepts is key to cracking interviews for roles such as Front-End Developer, JavaScript Developer, UI Engineer, and Full-Stack Developer.

Additionally, real-world coding problems, JavaScript coding challenges, and hands-on interview questions will test your problem-solving ability and help you master writing clean and efficient code.

For those preparing for interviews involving React, Angular, Vue.js, or Node.js, a strong foundation in JavaScript is non-negotiable. That’s why our curated resources are not just theory-based — they also include practical scenarios and live code snippets that mirror real-world applications.

Whether you are a beginner brushing up on the basics or an experienced developer preparing for high-level system design and architecture questions involving JavaScript, this category provides everything you need to succeed.

Questions in: Javascript

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