[jQuery] Change the date format of jquery calendar

[Praveen]

Hi all i have one jquery calendar

$('selector').datePicker(); which is giving me in dd/mm/yyyy

i want to change this format to yyyy-mm-dd

i tried with
$.datePicker.setDateFormat('ymd','-');

error: $.datePicker is undefined

and tried with this code

$("#sd").datepicker.setDateFormat('ymd','-');

error: $("#sd").datepicker.setDateFormat is not a function