tablesorter demo not working

tablesorter demo not working

Hello.  I'm having trouble getting the tablesorter demo example to work properly.  It's at http://tablesorter.com/docs/example-ajax.html

I'm not implementing this in my own application, it's not working on the tablesorter.com web site itself. Here is the table, in the order as it exists in the html:

First Name Last Name Age Total Discount Date
Peter Parker 28 $9.99 20% Jul 6, 2006 8:14 AM
John Hood 33 $19.99 25% Dec 10, 2002 5:14 AM
Clark Kent 18 $15.89 44% Jan 12, 2003 11:14 AM
Bruce Almighty 45 $153.19 44% Jan 18, 2001 9:12 AM
Bruce Evans 22 $13.19 11% Jan 18, 2007 9:12 AM

After I click the "Append new table data " link, I'm expecting the update trigger to sort the table, but it isn't happening:

First Name Last Name Age Total Discount Date
Peter Parker 28 $9.99 20% Jul 6, 2006 8:14 AM
John Hood 33 $19.99 25% Dec 10, 2002 5:14 AM
Clark Kent 18 $15.89 44% Jan 12, 2003 11:14 AM
Bruce Almighty 45 $153.19 44% Jan 18, 2001 9:12 AM
Bruce Evans 22 $13.19 11% Jan 18, 2007 9:12 AM
Bruce Almighty 45 $153.19 44% Jan 18, 2001 9:12 AM
John Hood 33 $19.99 25% Dec 10, 2002 5:14 AM
Peter Parker 28 $9.99 20% Jul 6, 2006 8:14 AM
Bruce Evans 22 $13.19 11% Jan 18, 2007 9:12 AM
Clark Kent 18 $15.89 44% Jan 12, 2003 11:14 AM

Neither First Name nor Age is sorted.  If I click the column heading, it sorts properly, but I expected this to be sorted as specified in the JavaScript without having to click a column heading.  Am I missing something?  Thanks.