A web browser is a software application for retrieving, presenting and traversing information resources on a local machine, intranet or on the World Wide Web. The primary purpose of a web browser is to bring information resources to the user ("retrieval" or "fetching"), allowing them to view the information ("display", "rendering"), and then access other information ("navigation", "following links"). (1) Some popular browsers are: Internet Explorer, Firefox, Google Chrome, Opera, Safari and Konquerer. A mobile app is a computer program designed to run on smartphones, tablet computers and other mobile devices.

The browsers high level structure:

web browser layers

Quick reference to Browsers at:

  1. Definition - browser
  2. Explanation of how browsers work 1
  3. Technical Spec - Refer to DOM