An AngularJS, Bootstrap, jQuery, Sass web based wireframe editor. You can check the demo at http://editor.davelinke.com/
This project makes use of the AngularJS two way data binding capabilities in order to create a visual HTML/Wireframe editor.
The project is still in construction (maybe not even alpha) but there is the ground work of the functioning of the GUI.
It is also the early stage of the online prototyping tool http://pinocchio.us