How to add calender or datepicker in Joomla 3 or Joomla 2.5

How to add calender or datepicker in Joomla 3 or Joomla 2.5 :

JHTML::_('behavior.calendar');
JHTML::_('behavior.tooltip');

<?php echo JHTML::calendar('','published_date','inputdate','%Y-%m-%d'); ?>

where field name->published_date
and input id ->inputdate