Draw Arcs/Circle with Canvas: HTML5

http://technotip.com/3216/draw-arcs-circle-with-canvas-html5/

Today lets learn how to use arcs and paths to draw circle.

arc(x, y, r, sA, eA, TF);

arc takes 6 parameters. x and y is the x-axis and y-axis, which is the center of the circle. i.e., The x and y parameters determine where the center of the circle will be located on your canvas.

... https://www.youtube.com/watch?v=vE0bstctkp4