A web browser is a computer program which downloads and displays web pages on the World Wide Web (or a local device). Its main purpose is to load and display graphical pages on the internet. The original internet browser was NCSA Mosaic. Before long, however, Netscape and AOL became most popular, while NCSA Mosaic became obsolete.
There are five major web browsers currently in use; Internet Explorer (replaced by Edge), Firefox, Safari, Opera, and Chromium-based browsers, including Google Chrome. IE currently holds the largest "market share" in desktop browsing but this is being eroded by mobile phone and tablet browsers from Apple and Google. The independent browsers Opera and Firefox are well positioned and compete across multiple platforms.