no support for the <abbr> element which is part of the HTML 4.01 standard prior to IE 8. There were also some CSS attributes missing from MSHTML, like min-height, etc. as of IE 6. As of Internet Explorer 8 CSS 2.1 is fully supported as well as some CSS 3.0 attributes. This lack of standards compliance has been known to cause rendering bugs and lack of support for modern web technologies, which often increases development time for web pages. Still, HTML rendering differences between standards-compliant browsers are not yet completely resolved. Microsoft alternatives Apart from MSHTML, Microsoft also has and uses several other layout engines. One of them, known as Tasman, was used in Internet Explorer 5 for Mac. Development of Internet Explorer for Mac was halted in roughly 2003, but development of Tasman continued to a limited extent, and was later included in Office 2004 for Mac. Office for Mac 2011 uses the open source WebKit engine. Microsoft's now defunct web design product, Expression Web as well as Visual Studio 2008 and later do not use Internet Explorer's MSHTML engine, but rather a different engine. In 2014, MSHTML was forked to create the engine EdgeHTML for Microsoft Edge on Windows 10. The new engine is "designed for interoperability with the modern web" and deprecates or removes a number of legacy components and behaviors, including document modes, ensuring that pure, standards-compliant HTML will render properly in browsers without the need for special considerations by web developers. This resulted in a completely new browser called Microsoft Edge (now referred to as "Microsoft Edge Legacy"), which replaced Internet Explorer as a stock browser of Windows and a base of Microsoft's web related services until its replacement with a Blink and Chromium based Microsoft Edge in late 2020. See also Comparison of browser engines References External links Internet Explorer Layout engines