Problem with updating dates

Hello.

I just discovered a bug with date range. If I update dates with a date range, both startdate and enddate are reseted to the current date.

I investigate and the problem was at line around 1575 with this line:
`
var date_span_option = widget_element.find('input:radio[name="date-span"]:checked').val();
`

after several tests, I found the problem was the :checked attribute which is not recognized. So the variable date_span_option is marked as undefined.

Tested on FF33 and Chrome39.