Often you would like to export or save image generated on canvas.
here is simple script which does exactly the same.
to get string output to save image you can use stringOutput.
If you run following script you might get following error
Uncaught Error: SECURITY_ERR: DOM Exception 18
As browser can’t set cookies on file://, to run successfully you have to host file on web server.
var c = document.getElementById("sketch");
var dataString = c.toDataURL("image/png");
var index = dataString.indexOf( "," )+1;
var stringOutput = dataString.substring( index );