Microsoft Expression Web, code-named Quartz, is an HTML editor and general web design software product by Microsoft. It is available free of charge from Microsoft and is a component of the discontinued Expression Studio.Expression Web can design and develop web pages using HTML5, CSS 3, ASP.NET, PHP, JavaScript, XML+XSLT and XHTML. Expression Web 4 requires .NET Framework 4.0 and Silverlight 4.0 to install and run.