Web Application Introduction

What is Web Application ?

A web application is a software or program which is accessible using any web browser. Its frontend is usually created using languages like HTML, CSS, Javascript, which are supported by major browsers.

A web applications have two type of components:

1. Client Side Components
2. Server Side Components

Client Side Components :

These components are used to create client side application.

Used when the users browser already has the code.

Web browser executes the client side scripting.

Can not be used to connect to the databases on the Web Server.

Can not access the file system that resides at the web server.

Response from a client side script is faster as compared to server side script.

For Example : Html, Css, Javascript, Jquery etc.

Server Side Components :

These components are used to create server side application.

Used to create dynamic pages.

Web server executes the server side program or script.

Used to connect to the databases that reside on web server.

Can access the file system residing at the web server.

Response from a server side is slower as compared to a client side script.

For Example : servlet, jsp etc.

Why you need a Web Application ?

There are follwing reasons to need a Web Application:

1. Performance – Because the Presentation tier can cache requests, network utilization is minimized, and the load is reduced on the Application and Data tiers.

2. Its provide better re-usability.

3. Improved Data Integrity.

4. Improved Security – Client is not direct access to database layer.

5. Forced separation of user interface logic and business logic.

6. Easy to maintain, to manage, to scale, loosely coupled etc.

7. High performance, lightweight persistent objects.

8. Scalability – Each tier can scale horizontally.

9. Data availability 24*7.

Web Application vs Web Site

Web Application	WebSite
It is used to perform interaction with the end user.	It contains the static content that is accessible to all visitors.
It is the part of web site that mean itself not a complete website.	It is a complete website that can be access from browser.
It must be precompiled before deployment.	It doesn't need to be pre-compiled.
It is not only read the page content but also manipulate the restricted data.	Its content can view and read.
It needs the authentication.	Authentication is not obligatory for informational websites.