Here is the code example of canvas. The example is just drawing one line from (10,10) to (80,80). The output is shown under the code box.
The good resource on HTML5 canvas tag is w3schools.com
Here is one more link if you want learn more on canvas element in HTML5. http://thinkvitamin.com/code/how-to-draw-with-html-5-canvas/ How to Draw with HTML 5 Canvas By Jamie Newman