Canvas.toDataURL（）解决方法？

Question

Okay, so a friend of mine asked me to help him out with creating a canvas painting application for a mobile site he's working on. However, he was unable to get the "paintings" to save to the server. I did a little checking and it appears that in the current iteration of the browser (based on WebKIt IIRC), .toDataURL support was randomly thrown out. Is there any workaround for this that'll allow the canvas data to be sent via a POST request?

Edit:

Browser- Netfront(R) Browser, NX v.1.0

It simply appears that the browser doesn't support it

canvas = document.getElementById('paint');
var imagedata = canvas.toDataURL();
var datafield = document.getElementById('dataurl');
datafield.value = imagedata;
document.forms["imagedatahold"].submit(); 

On the file that is to receive the data, the querystring is empty. This is not the case in any other browser as far as I can tell.

The value of "imagedata" is returning as:

data:,

Answer 1

I used to have a problem with a web app running on android devices.
The problem was that android didn't have a toDataURL method implementation, so I ended up using this implementation : http://code.google.com/p/todataurl-png-js/ .
It may be a bit slower, but it gets the job done.