Web application

Single-page and progressive are two approaches for a website to seem more like a native app.

History

In earlier computing models like client-server, the processing load for the application was shared between code on the server and code installed on each client locally. In other words, an application had its own pre-compiled client program which served as its user interface and had to be separately installed on each user's personal computer. An upgrade to the server-side code of the application would typically also require an upgrade to the client-side code installed on each user workstation, adding to the support cost and decreasing productivity. In addition, both the client and server components of the application were usually tightly bound to a particular computer architecture and operating system and porting them to others was often prohibitively expensive for all but the largest applications (Nowadays, native apps for mobile devices are also hobbled by some or all of the foregoing issues).


In 1995, Netscape introduced a client-side scripting language called JavaScript, allowing programmers to add some dynamic elements to the user interface that ran on the client side. So instead of sending data to the server in order to generate an entire web page, the embedded scripts of the downloaded page can perform various tasks such as input validation or showing/hiding parts of the page.^[2]


In 1999, the "web application" concept was introduced in the Java language in the Servlet Specification version 2.2. [2.1?].^[3] At that time both JavaScript and XML had already been developed, but Ajax had still not yet been coined and the XMLHttpRequest object had only been recently introduced on Internet Explorer 5 as an ActiveX object.


Applications like Gmail started to make their client sides more and more interactive since early 2000s. A web page script is able to contact the server for storing/retrieving data without downloading an entire web page. The practice became known as Ajax in 2005.^[4]


"Progressive web apps", the term coined by designer Frances Berriman and Google Chrome engineer Alex Russell in 2015,^[5] refers to apps taking advantage of new features supported by modern browsers, which initially run inside a web browser tab but later can run completely offline and can be launched without entering the app URL in the browser.

Development

Writing web applications is simplified with the use of web application frameworks. These frameworks facilitate rapid application development by allowing a development team to focus on the parts of their application which are unique to their goals without having to resolve common development issues such as user management.^[8] Many of the frameworks in use are open-source software.


In addition, there is potential for the development of applications on Internet operating systems, although currently there are not many viable platforms that fit this model.