THE "WHAT"
In simple terms, Web Applications (Web Apps) are software programs that are stored on remote servers and delivered over the Internet through web browser interfaces. In other words, Web Applications allow website visitors to submit and retrieve data to/from a database over the Internet using their preferred desktop or mobile web browser. The data is then presented to the user within their browser as information is generated dynamically (in a specific format, e.g. in HTML using CSS) by the web application through a web server. The web browser is a key component – it interprets the data and runs all scripts before and while displaying the requested pages and content. Wikipedia terms the web browser as the “universal client for any web application”.
One of the advantages of Web Applications over Desktop Applications is that they perform their function irrespective of the operating system and browsers running client side. Web applications are quickly deployed anywhere at no cost and without any installation requirements (almost) at the user’s end.