QuarkXPress 10 does not offer the ability to export HTML anymore. The web layout in QuarkXPress 9 exports static web sites using table-based HTML4. The world demands for highly interactive, CSS based web pages, often driven from a CMS. The web layout in QuarkXPress, introduced with QuarkXPress 5 in 2002, just didn't fit into the present demand and expectations.
That said, for the future we have some compelling ideas for Digital Publishing, especially for web publishing, so please stay tuned. And as QuarkXPress 10 heavily concentrates on HTML5 for Digital Publishing, it will be all around HTML5.
Important note: As QuarkXPress 10 will not open projects that contain a web layout, you need to convert these layouts to a Print layout first in QuarkXPress 7, 8 or 9. Then open the new print projects in QuarkXPress 10.
For more information please refer: http://forums.quark.com/t/33059.aspx