Maqetta is an open source project hosted by the Dojo Foundation

Visual authoring of HTML5 user interfaces - in the browser!

Maqetta is an open source project that provides WYSIWYG visual authoring of HTML5 user interfaces. The Maqetta application itself is authored in HTML, and therefore runs in the browser without requiring additional plugins or downloads.
Preview 5.0.1 release is now available, running on Web at Maqetta.org or via download.
Sometime soon (probably 3pm US-CT), the site will be coming down briefly to upgrade to Preview 5.0.1. More info can be found here.