Disable past date in jQuery datepicker

Change at line no at 8.

1.    onSelect:function ( selectedDate ) {
2.   var option = this.id == "startDate" ? "minDate" : "maxDate",
3.   instance = $(this ).data( "datepicker" ),
4.   date = $.datepicker.parseDate(
5.   instance.settings.dateFormat ||
6.   $.datepicker._defaults.dateFormat,
7.   selectedDate, instance.settings );
8.   date.setYear(date.getYear()+1);
9.   dates.not( this ).datetimepicker( "option", option, date );