IE 5.1 for Mac OS 8 and 9 was released on December 18, 2001. This was updated later, and the release of Mac OS X v10.1 on Septemincluded the final version of Internet Explorer 5.1 for Mac OS X. The release of Mac OS X 10.0 on Maincluded yet another preview of the Mac OS X version of IE 5. The Mac OS X Public Beta included another preview of the Mac OS X version of IE. The initial release was just for Mac OS 8 and Mac OS 9, however two months after that release on May 15 a Mac OS X version was released, bundled with the Mac OS X DP4 release handed out to developers at the 2000 Worldwide Developers Conference. Preview releases of the browser included a feature called the MediaBar which integrated MP3 and internet radio playback, but this feature was dropped from the final version. It also included an Auction Manager for tracking auctions in sites like eBay and an Internet Scrapbook to allow users to quickly and easily store and organize web content (for example an image or a piece of selected text). It also introduced a number of features that were later added to other browsers such as complete support for the PNG image standard (which previous versions did not support at all), DOCTYPE switching, Text Zoom and XML source view. The Macintosh Edition introduced a new rendering engine called Tasman that was designed to be more compliant with emerging W3C standards such as HTML 4.0, CSS Level 1, DOM Level 1, and ECMAScript.

The Windows version of Internet Explorer 5 had been released a year earlier, but used the Trident layout engine. Another year later, on January 5, 2000, Microsoft announced a new version of Internet Explorer at the San Francisco Macworld Expo, Internet Explorer 5 Macintosh Edition which was released two months later on March 27, 2000.

Internet explorer macos