var canvas = document.getElementById('tutorial');

  // Make sure we don't execute when canvas isn't supported

  if (canvas.getContext){

    // use getContext to use the canvas for drawing

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

    // Filled triangle

    ctx.beginPath();

    ctx.moveTo(25,25);

    ctx.lineTo(105,25);

    ctx.lineTo(25,105);

    ctx.fill();

    // Stroked triangle

    ctx.beginPath();

    ctx.moveTo(125,125);

    ctx.lineTo(125,45);

    ctx.lineTo(45,125);

    ctx.closePath();

    ctx.stroke();

  }