Add fonctionnality to JQuery UI Datepicker to keep date bofore change
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I need to add functionality to JQuery UI Datepicker.
I need to keep current (previous) datepicker date before date changes and set new function method to datepicker to tell if previous date < next date or previous date > next date.

For exemple I would like to have :

    $("#myInput").datepicker.("getDirection"); // => 'left' if previous date < next date or => 'right' if previous date > next date