Why does canvas.toDataURL() throw a security exception?

Question

Did I not get enough sleep or what? This following code

var frame=document.getElementById("viewer"); frame.width=100; frame.height=100;  var ctx=frame.getContext("2d"); var img=new Image(); img.src="http://www.ansearch.com/images/interface/item/small/image.png"  img.onload=function() {     // draw image     ctx.drawImage(img, 0, 0)      // Here's where the error happens:     window.open(frame.toDataURL("image/png")); } 

is throwing this error:

SECURITY_ERR: DOM Exception 18 

There's no way this shouldn't work! Can anyone explain this, please?

Answer 1

In the specs it says:

Whenever the toDataURL() method of a canvas element whose origin-clean flag is set to false is called, the method must raise a SECURITY_ERR exception.

If the image is coming from another server I don't think you can use toDataURL()