Setting Enddate for Datepicker

Setting Enddate for Datepicker

Hey guys,

I'm really new to this so please excuse me if this is too easy,
I just integrated the Date picker with a start and end date.
Now I want the end date to be set automatically to 7 Days after the StartDate, once that is selected.

For now, it looks like this. Any help is appreciated!(excuse my English)

    $( function() {
        var dateFormat = "mm/dd/yy",
          from = $( "#from" ).datepicker({
              defaultDate: "+1w",
              changeMonth: true,
              numberOfMonths: 1,
              onSelect: function(){
                var date = $(this).datepicker('getDate');
                if(date){
                  date.setDate(date.getDate()+1);
                  $("#to").datepicker("option", "minDate", date);
                }
              }
            });

          to = $( "#to" ).datepicker({
            defaultDate: "+1w",
            changeMonth: true,
            numberOfMonths: 1,
            onSelect: function() {
         var date = $(this).datepicker('getDate');
             if (date) {
                  date.setDate(date.getDate() - 1);
                       $( "#from" ).datepicker( "option", "maxDate", date );
                           }
                     }
          })

        function getDate( element ) {
          var date;
          try {
            date = $.datepicker.parseDate( dateFormat, element.value );
          } catch( error ) {
            date = null;
          }

          return date;
        }
      } );