More specifically...
1)
Set up your survey to use JavaScript.
2) Add the following script to the source of the date question. Replace "QQ" with the date
question ID.
The script resets the max and min date options of the datepicker.
<script type="text/javascript" charset="utf-8">
$(document).ready(function () {
$(document).ready(function(){
$('#questionQQ .popupdate').datepicker( 'option', 'minDate', new Date(2012, 8 - 1, 13) );
$('#questionQQ .popupdate').datepicker( 'option', 'maxDate', new Date(2012, 8 - 1, 25) );
});
</script>
