I'm trying to figure out how does work the new offset(index, coord) method.
There isn't an exemple for this method in the jQuery documentation.
So, I set up a very simple test case in order to inspect the function parameters index and coord.
It is hosted at: http://jsbin.com/opufi/

The first alert works as expect and then the script stops returning the following error:
b is undefined (var b is from the jQuery library).
Is this a bug, or am I missing something?