Internet Explorer for Mac OS X (also referred to as Internet Explorer for Macintosh, Internet Explorer Macintosh Edition, Internet Explorer:mac or IE:mac) is a proprietary web browser developed by Microsoft for the Macintosh platform to browse web pages. Initial versions were developed from the same code base as Internet Explorer for Windows. Later versions diverged, particularly with the release of version 5, which included the cutting-edge, fault-tolerant and highly standards-compliant Tasman layout engine.