Draw Line, Circle, Ellipse (Oval), Polyline, Polygon, Rectangle

This JavaScript VectorGraphics library provides graphics capabilities for JavaScript: functions to draw circles, ellipses (ovals), oblique lines, polylines and polygons (for instance triangles, rectangles) dynamically into a webpage.

http://www.walterzorn.com/jsgraphics/jsgraphics_e.htm

It was very very useful to me.