calendar error

I have a question is about to get type of the values of the calendar, the result is to return to"Thu Jul 05 2012 14:48:00 GMT+0800"

{type:'calendar',label:'s_time',name:'c10',dateFormat: "%Y-%m-%d",calendarPosition: "right"}, {type:'calendar',label:'e_time',name:'c11',dateFormat: "%Y-%m-%d", calendarPosition: "right"}

When I submitted, obtain c10, c11, their values are Thu Jul 05 2012 14:48:00 GMT + 0800, not 2012-07-06

Try to replace the files i’ve attached
f.zip (317 KB)