A Web-Based Applications A web-based application is any program that is accessed over a network connection using HTTP, rather than existing within a device's memory. Web-based applications often run inside a web browser. However, web- based applications also may be client-based, where a small part of the program is downloaded to a user's desktop, but processing is done over the internet on an external server. In computing, a web application or web app is a client-server computer program that the client (including the user interface and client-side logic) runs in a web browser. Common web applications include webmail, online retail sales, online banking, and online auction. In contrast, web applications use web documents written in a standard format such as HTML and JavaScript, which are supported by a variety of web browsers. Web applications can be considered as a specific variant of client-server software where the client software is downloaded to the client machine when visiting the relevant web page, using standard procedures such as HTTP. Client web software updates may happen each time the web page is visited. During the session, the web browser interprets and displays the pages, and acts as the universal client for any web application. In the early days of the Web, each individual web page was delivered to the client as a static document, but the sequence of pages could still provide an interactive experience, as user input was returned through web form elements embedded in the page markup. However, every significant change to the web page required a round trip back to the server to refresh the entire page. This book is designed for college students as an introduction to developing applications for the Web.