Hello All, Gecko 2.0 ships with a non-standard method on <canvas> named mozGetAsFile(contentType, fileName). We added this for internal use in our UI. It retrieves the contents of the canvas as a File object (at the time Gecko did not supports Blobs) encoded in the contentType according to the same rules toDataURL uses.
I propose adding a toBlob(contentType) method to the canvas element in the style of toDataURL. This would greatly increase the options available to developers for extracting data from a canvas element (a Blob can be saved to disk, XHRed, etc.) - Kyle
