Andreas Herz has added diagramming features (connectors, ports, tool selection) on top of Walter Zorn’s famous DHTML graphics library to create Open jACOB Draw2D. There are several interactive demos that let you create simple diagrams. There is also javadoc style documentation (though it mostly documents the class hierarchy).

I think a discussion of the underlying wz_jsgraphics library (which Depicter.com currently also uses) is in order. First of all, the good: this approach works in all Javascript-enabled browsers (in particular, Flash is not needed). But wz_jsgraphics is rather inflexible: it’s merely a compiler for a few graphics primitives (lines, filled rectangles and XY-alligned ellipses) to an “assembly” language consisting of stacked DIVs. Because the library doesn’t keep track of the DIVs associated with each primitive, there’s no way to undo a shape (short of clearing the entire drawpad). wz_jsgraphics can also be slow (anything but rectangles and horizontal / vertical lines requiring large number of DIVs). However, these shortcomings aren’t fatal for a diagramming application.

Open jACOB is supposed to be a bigger framework, including a server-side part, though at the moment there isn’t much to see besides Draw2D. Overall, this is a promising start; hopefully this project will stay active and yield (further) useful results.