<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
<p><canvas width="500" height="200" id="c"></canvas></p>
<script type="text/javascript">

  var canvas = document.getElementById('c');
  var ctx = canvas.getContext('2d');

  ctx.beginPath();

  ctx.lineWidth = 20;
  ctx.strokeStyle = 'rgb(0,0,0)';

  ctx.save();

  ctx.moveTo(10, 30);
  ctx.lineTo(50, 50);

  ctx.stroke();
  ctx.restore();

  ctx.lineTo(80, 80);
  ctx.stroke();

</script>
</body>
</html>