Circles on canvas

hey - was looking fwd to kirupas tut - but it brings up a 404. Alas … >
I have a little Q re:canvas, and drawing multiple circles … and rendering them ::
In my ‘render’ function which draws the objects on the stage … I am using the same code multiple times … And ps - i want to do this OUTSIDE of a for loop - cos when you use a for loop, as each object does different things.

stage.arc(ball.x, ball.y, radius, 0, 2 * Math.PI, false);
stage.fillStyle = "rgba(0,0,255,0.1)";

is my code for a circle … but can i put this into a function and spit it out where it needs be, rather than duplicating as many times as i am … thanks!:egg: