php / mysql / js search result question

Hi List, I have a very long list of customer names which i know is easy to get from a mysql result using php, no prob there. But what i would like to do is offer input box and when the user enters a letter, i think this will require client side onchange(), the full list, i think might be in an iframe, will move to the first instance of user input. Example: 1 Alpha Customer 2 Apple Customer 3 Beta Customer 4 Crazy customer 5 Doppy customer User input is "a" so the list moves to first instance of "a". User continues to input "ap" so the list moves to "2 Apple Customer" and so on. If the user had input "d" then the list would move to "5 Doppy customer" and i suppose this could become selected ready for the user to hit the return key to select this customer. I would prefer to not do multiple "POSTS" and return result, which i can do already, so i think some natty client side JS might do the trick but i have very little knowledge of this. Any urls or direct help / advise is gratefully received. Thank you in advance Dave c