I have been tasked to develop a web based offer request application for bathrooms and I am asking opinions on which tool should I choose. I have narrowed options down to two (html5 and silverlight). Most of the application consists of basic UI elements that could be achieved with html4. However most challenging part is the design view for the bathroom.

User first defines size of the bathroom by giving dimensions. When the dimensions are defined the application renders an empty bathroom floorplan and user can start dragging&dropping furniture on to it. Some furniture have rules where they can be dragged. For example sinks can only be dragged next to a wall.

I know that this functionality can be achieved with silverlight but what about html5 ? I know that Canvas element can be used to draw graphics, but can it render the bathroom smoothly as user drags a piece furniture on it?