A script like this will disable weekends and some holidays in the Bootstrap Datepicker (dates depend on your format setting):
Sample survey attached:
<script type="text/javascript" charset="utf-8">
$(document).ready(function(){
// Disable weekends
$('#answer{SGQ}_datetimepicker').data('DateTimePicker').daysOfWeekDisabled([0,6]);
// Disable holidays
$('#answer{SGQ}_datetimepicker').data('DateTimePicker').disabledDates(['04-09-2017', '09-10-2017', '25-12-2017', '26-12-2017', '01-01-2018']);
});
</script>Sample survey attached: