If you are beginner in HTML5 Canvas, try to learn it step by step. Go to the following links. You can find new thing from each HTML5 Free Code and example easyly.
Canvas- Lines with Different Ending and Joining Styles
Canvas- Draw Polygons with Shadow Effect
Canvas- Use Writing Features to Draw Texts
Canvas- Image Patterns as Filling and Drawing Styles
Canvas- Select an Object by Mouse Click (Hit Detection)
Canvas- Coordinate System Transformation, Scaling and Shearing the Context