Whiteboard lets the user draw freehand graphics on a Web page.
It can create a canvas object for the whiteboard (if one does not exist) and let the user draw
on the canvas area by dragging the mouse around.
The color,
thickness,
line join, and line cap of the drawing pen can be configured.
The object can also clear the whiteboard,
export the coordinates of the drawn lines, or import
previously drawn lines.
