eSearch Widget - autocomplete search

[MayJeff]

Is anyone try to write a function for search like these two samples: http://gis.greeleygov.com/origin/propinfo.html or http://www.arcgis.com/home/item.html?id=4a61e3e4b0c94300a3a361855d9a344f when you type on the search box for address, it gives you autocomplete search?  Something like google search as well, not neccessary need to show all the dop down list.

[MayJeff]

I would like to perform a search just like Rebert has on his own gis site able to show some autocomplete search information for users.  It is a really feature.  Can you give me some ideas how to do so?  Thank you.