fullCalendar - change background color of days before today with weekend = false

fullCalendar - change background color of days before today with weekend =
false

The question has been already answered (How to change background color of
days before today in FullCalendar...?) for a fullCalendar with weekends =
true. Therefore there will always be a today date on the Calendar and we
could use the following code to pick up previous dates:
$('.fc-today').prevAll('td').css('backgroundColor','yellow');
$('.fc-today').parent().prevAll().find('td').css('backgroundColor','yellow');
How would we go about locating previous dates if we have weekends = false?
This means that on Sat and Sun there is no fc-today to search for.