var w = document.getElementById('picklistid').selectedIndex;
var selected_text = document.getElementById('picklistid').options[w].text;
selected_text variable will be returned the combo box selected text.
select curdate() | 3/10/2011 |
select curdate()-1 | 20110309 |
select curdate() - INTERVAL 1 DAY | 3/9/2011 |