How to select year only from Calendar Extender

Hi:

I hope to make the calendar extender to show  year only , not show month or day, 

I have tried following codes:

function ChangeCalendarView(sender,args)
{
sender._switchMode("years", true);            
}

however, the effects not meet the hope, since it only show year at first, but still will show month and days.

And after doing some research, I found some codes about year/month, like following:

http://weblogs.asp.net/aghausman/how-to-show-and-select-month-year-in-calendar-extender

it can work for year/month, but if I want year only, how to modify that. 

It is not so clarify to change it. Any instructions is appreciated, thanks a lot.