Canvas How to - Output data URL for png image from canvas

Question

We would like to know how to output data URL for png image from canvas.

Answer


<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'>
window.onload=function(){<!--from  w w w .j  a  v  a  2s .  c  o  m-->
    var canvas = document.getElementById('canvas');
    canvas.width = 200;
    canvas.height = 150;
    var context = canvas.getContext('2d');
    context.rect(20,20,50,50);
    context.stroke();
    var image = new Image();
    image.onload = function(){
      context.clearRect(0, 0, canvas.width, canvas.height);
      context.drawImage(image, 0, 0);
    }
    image.src = canvas.toDataURL("image/png");
}
</script>
</head>
<body>
  <canvas id="canvas"></canvas>
</body>
</html>

The code above is rendered as follows: