TopStyle is a HTML/XHTML/CSS editor designed for Microsoft Windows systems. It is developed by Nick Bradbury and released on December 2012. This program features code-centric editing instead of What You See Is What You Get or WYSIWYG. It also offers integrated preview support for third party layout engines like Internet Explorer Trident, Mozilla Gecko, or Apple Inc. Webkit.
TopStyle handles editing compatibility with several programming languages particularly XHTML, HTML, and CSS. It is likewise capable of handling browser compatibility checking and standards checking. Checking procedure encompasses several levels even up to as strict as W3C CSS. Browser checking is available for a variety of browsers including Safari, Internet Explorer, Firefox, and Opera. It also has the added functionality of visually showing which code strings are incompatible, as well as provide warning messages regarding the details of the issue or incompatibility. TopStyle also handles offline validation services for XHTML and HTML syntax through CSE HTML Validator. This validating function is also useful for checking links.