What is a web application and how does it work?
A web application (web app) is software you use through a web browser such as Chrome, Firefox or Safari.
- Client: your phone or computer with the browser.
- Web server: a powerful computer that runs the app.
- Database: where the app stores data (seats, users, orders).
Flow: you fill a form and press a button → the browser sends a request → the server checks and updates the database → it sends a response page back.
Website vs web app: a simple website mainly shows information (read only). A web app lets you do things: log in, fill forms, book, pay, submit.
Advantages: no installation, works on any device with a browser, always the latest version, data shared live. Limits: needs internet, can be slow on weak networks, security risks.
Online reservation
Used to book train, bus and flight tickets, hotel rooms, cinema seats and doctor appointments.
- Register / log in.
- Enter from, to, date and class; search.
- See availability from the database.
- Choose seat, enter passenger details.
- Pay online.
- Get an e-ticket with a booking number (PNR) by SMS/email.
Why it works: one shared database stops two people booking the same seat. Benefits: book from home 24×7, compare options, cancel online.
E-governance
E-governance means using ICT to deliver government services and information to citizens.
- Applying for birth, income or caste certificates.
- Filing income tax, paying bills and fines.
- Passport and driving licence applications.
- Land records, scholarship and pension portals, digital document lockers.
Types: government to citizen (G2C), government to business (G2B), government to government (G2G). Benefits: saves time and travel, more transparent, less paper, can track status. Challenges: digital divide, cyber security, privacy.
E-learning
E-learning is learning through digital devices and the internet.
- Video lessons, e-books, online quizzes, virtual classrooms (live video), learning management systems.
- Open courses (MOOCs) from universities across the world; India's SWAYAM and DIKSHA are examples.
Benefits: learn at your own pace and place, replay lessons, instant quiz results. Limits: needs a device and data, less face-to-face contact, self-discipline needed.
E-commerce
E-commerce is buying and selling goods and services online.
- Search or browse products.
- Add to cart.
- Log in and give address.
- Pay: card, UPI, net banking, wallet or cash on delivery.
- Get confirmation and track delivery.
Types: B2C (business to consumer), B2B, C2C (people selling to people). Safe use: buy only from trusted sites with HTTPS (lock icon), never share OTP or PIN, check reviews and return policy, beware of fake offers (phishing).
Try it yourself
Browse a booking or shopping site without paying: find the search box, the results from the database and the HTTPS lock. Then book seats in the 3D and watch the count.
Key formulas and definitions
- Web app = client (browser) + web server + database
- Request → server processes → response page
- Website = mainly read; web app = interact (log in, book, pay)
- E-governance types: G2C, G2B, G2G
- E-commerce types: B2C, B2B, C2C
- HTTPS lock = data encrypted between browser and server
Worked examples
1. A train coach has 72 berths. 58 are booked online. How many are free, and why can't two people book the same berth?
72 − 58 = 14 free. All bookings update one shared database on the server, so once a berth is booked, every user sees it as taken.
2. Is an online income-tax filing portal G2C, G2B or G2G?
G2C (government to citizen), because citizens use it to file their own returns. A portal for companies to file returns would be G2B.
3. You get an SMS: "Your parcel is held, pay ₹10 at this link". The link has no HTTPS and a strange spelling. What should you do?
Do not click or pay. It is likely phishing. Check order status only on the official shopping app or site, and report the message.
Common mistakes
- Thinking a web app is installed like a phone game. It runs on a server and opens in the browser.
- Calling every website a web app. A web app lets you interact: log in, submit, book or pay.
- Sharing an OTP with a caller who says they are from the bank or shop. No genuine company asks for OTP.
- Thinking e-governance is only for tax. It covers certificates, licences, land records, pensions and more.