If I may piggy back on the same problem. The source is below. When you first load the HTML in a browser (any browser) it shows the original dates, after trying to sort it gets weird.

Initial dates:

2011-01-01
2011-01-02
2011-10-01

Become:

04-07-2006
03-04-2007
04-07-2007

Format options:

formatoptions:{srcformat:'Y-m-d',newformat:'d-m-Y'}

Desired outcome:

01-01-2011
02-01-2011
01-10-2011

Source: