What Is a Web App? How Does It Work? Pros and Cons of Web Applications

In software technology, a web application (often abbreviated as a web app) is an application or program that users can access, communicate with, and interact through the Internet using web browsers.

1. What Is a Web Application?

Web Application (Web App) is a type of computer program that typically runs on the Internet. Unlike desktop applications, web applications are usually hosted on cloud servers. Web applications can be accessed from anywhere using web browsers such as Firefox, Microsoft Edge, Google Chrome, or Apple Safari.

This means that to use a Web Application, you do not need to download or install it on your device. Instead, you simply use a web browser. The browser resolves the Domain Name Server (DNS) to locate where the web application is hosted. After that, users and the system interact with each other based on the Client–Server model.

2. History and Evolution of Web Applications

Web applications have evolved from simple static web pages into highly complex applications capable of handling multiple tasks, delivering high performance, and meeting diverse user requirements across many industries today.

• HTML and TCP/IP Protocol: In the 1960s, Tim Berners-Lee introduced HTML (Hypertext Markup Language) and the TCP/IP protocol, laying the foundation for accessing information over the Internet.
• Netscape Navigator and JavaScript: In the 1990s, the emergence of Netscape Navigator and the JavaScript programming language enabled the creation of more interactive and complex websites.
• PHP and ASP.NET: The introduction of server-side languages such as PHP, ASP (Active Server Pages), and ASP.NET made it possible to develop more dynamic and sophisticated web applications.
• Ajax: Ajax (Asynchronous JavaScript and XML) improved interactivity and data synchronization between servers and browsers without requiring full page reloads, significantly enhancing user experience.
• Software as a Service (SaaS): This new approach to deploying web applications transformed how applications are delivered and consumed.
• Platform as a Service (PaaS): PaaS is a cloud computing service that provides platforms allowing users to develop and deploy their own applications over the Internet.

3. How Does a Web Application Work?

Web applications operate through interaction between a server and a user’s web browser. Below is the basic working process of a web application:

3.1 Request from the Web Browser

Users enter the domain of a Web App into the browser’s URL bar. The browser sends a request to a Domain Name Server (DNS), which resolves the domain name to the IP address of the server hosting the web app. The system then directs users to the web application, where interactions follow the Client–Server model.

3.2 User Interface

Web app developers must build a user interface that allows clients to send requests and receive responses from the server.

A Request is data sent from the client to the server, while a Response is the data returned by the server to the client. These responses are displayed through a pre-designed interface, known as the user interface.

The development of user interfaces for web applications is handled by Front-End developers. Common programming languages used include HTML, CSS, and JavaScript.

The term Front-End refers to the graphical user interface (GUI) that users directly interact with, such as navigation menus, buttons, images, layouts, and visual elements. Technically, a page or screen with UI components is represented by the Document Object Model (DOM).

Three core technologies influence how users interact with the front-end:

• HTML defines the structure of the front-end and DOM elements
• CSS (Cascading Style Sheets) controls layout, fonts, colors, and visual styling
• JavaScript adds dynamic functionality by manipulating the DOM

JavaScript enables dynamic updates on a page and displays new information without reloading. Front-end systems can handle basic user interactions, such as displaying calendars or validating email addresses, while forwarding more complex requests to the Back-End.

3.3 Server-Side Logic Processing

When users send requests from the client to the server, web applications process these requests and return responses. This process is known as Back-End processing.

When handling a request, the Back-End typically interacts with:

• Databases through queries to retrieve or modify relevant data
• Third-party APIs to gather additional information or perform extra functions

The Back-End uses various communication protocols and technologies to fulfill requests. It is capable of processing thousands of concurrent requests by applying parallel and concurrent techniques such as load balancing, caching, and data replication.

4. Key Advantages and Disadvantages of Web Applications

Like other application types, web applications have both strengths and limitations. Understanding these pros and cons will help determine whether web applications align with your goals.

4.1 Advantages of Web Applications

• Web applications are not limited to a specific platform.
• They can run on any platform that supports web browsers, including iOS, Android, and Windows.
• Web applications require less development time and manpower and do not need testing on multiple operating systems, resulting in lower development costs.
• Web apps use common cross-platform languages, making development and maintenance relatively easy.
• Automatic updates ensure users always access the latest version when opening the web app.

4.2 Disadvantages of Web Applications

• Web applications require a stable Internet connection. Without network access, users cannot use the application.
• Loading speed and response time depend on network conditions and server performance, which may lead to congestion.
• Despite security improvements, web apps still face risks of data breaches and unauthorized access.
• Compared to mobile or desktop applications, web apps may have limitations in UI customization and user experience across platforms.
• Ensuring browser compatibility can be challenging, as behavior may vary between browsers.
• Web applications can consume significant network and server resources, especially with high concurrent user traffic.