jCanvas Demo

https://github.com/caleb531/jcanvas

HTML

<script src="https://rawgit.com/caleb531/jcanvas/master/jcanvas.min.js"></script>
<canvas width="300" height="300"></canvas

CSS

canvas { border: 1px solid #ccc; }

JavaScript

// Draw a circle
$("canvas").drawArc({
  draggable: true,
  fillStyle: "green",
  x: 100, y: 100,
  radius: 50
});