A mobile browser (also called a microbrowser or minibrowser) is a web browser designed for use on a mobile device such as a mobile phone or PDA. Mobile browsers are optimized so as to display Web content most effectively for small screens on portable devices. Mobile browser software must be small and efficient to accommodate the low memory capacity and low-bandwidth of wireless handheld devices. Typically they were stripped-down web browsers, but as of 2006 some mobile browsers can handle latest technologies like CSS 2.1, JavaScript and Ajax.

Underlying technology

The mobile browser usually connects via a cellular network, or increasingly via Wireless LAN, using standard HTTP over TCP/IP and displays web pages written in HTML, XHTML Mobile Profile (WAP 2.0), or WML (which evolved from HDML). WML and HDML are stripped-down formats suitable for transmission across limited bandwidth, and wireless data connection called WAP. In Japan, DoCoMo defined the i-mode service based on i-mode HTML, which is an extension of Compact HTML (C-HTML), a simple subset of HTML.

WAP 2.0 specifies XHTML Mobile Profile plus WAP CSS, subsets of the W3C's standard XHTML and CSS with minor mobile extensions.

Newer microbrowsers are full-featured Web browsers capable of HTML, CSS, ECMAScript, as well as mobile technologies such as WML, i-mode HTML, or cHTML,.

Pioneers

The so-called microbrowser technologies such as WAP, NTTDocomo's i-mode platform and Openwave's HDML platform have fueled the first wave of interest in wireless data services.

The first deployment of a microbrowser was probably in 1997 when Unwired Planet (later to become Openwave) put their "UP.Browser" on AT&T handsets to give users access to HDML content.12

A British company, STNC Ltd., developed a microbrowser (HitchHiker) intended to present the entire device UI in 1997. The demonstration platform for this microbrowser (Webwalker) had 1 MIPS total processing power. This was a single core platform, running the GSM stack on the same processor as the application stack. In 1999 STNC was acquired by Microsoft and HitchHiker became Microsoft Mobile Explorer 2.0, not related to the primitive Microsoft Mobile Explorer 1.0. HitchHiker is believed to be the first microbrowser with a unified rendering model, handling HTML and WAP along with EcmaScript, WMLScript, POP3 and IMAP mail in a single client. Although it was not used, it was possible to combine HTML and WAP in the same pages although this would render the pages invalid for any other device. In addition, Amstrad's ill-fated e-m@iler and e-m@iler+ products used HitchHiker as their operating systems. Mobile Explorer 2.0 was available on the Benefon Q, Sony CMD-Z5, CMD-J5, CMD-MZ5, CMD-J6, CMD-Z7, CMD-J7 and CMD-J70.