Hi Ahmad,
Which datepicker? I can only answer for my one (
http://kelvinluck.com/assets/jquery/datePicker/v2/demo/ ) in which case
both of your questions are possible:
Is there a way to make the datepicker select future dates?
This is the default behaviour. You can customise it by passing a
startDate or endDate which changes the first and last selectable dates.
Is there a way to make the datepicker select specific days (ex.
Sundays and Wednesdays only) ?
Yes - you can do this using a renderCallback. You can see an example
with weekends disabled here:
http://kelvinluck.com/assets/jquery/datePicker/v2/demo/datePickerCustomCellRender.html
It should be easy to change the contents of the renderCallback function
to check if thisDate.getDay() is 0 or 3 (sunday or wednesday) rather
than checking for weekends.
Thanks
Hope that helps,
Kelvin :)