JavaScript code to take a screenshot of a website without using ActiveX

I have a JavaScript application that an user interacts with. I need to save the appearance of the interface at the current time, crop out the part that I need (or only shot the part that I need by specifying the div), and send it back to the server.

Clearly any external services would not be able to do this, I need a JavaScript (or Flash) script that can save the screen appearance. Is this possible?

Also, as the comment below says, I cannot use ActiveX.

Google is doing this in Google+ and a talented developer reverse engineered it and produced http://html2canvas.hertzen.com/ . To work in IE you'll need a canvas support library such as http://excanvas.sourceforge.net/