Hi,
I have a requirement for the following:

In a text box, as a word is being typed the closest match is highlighted in a list box below.
So for example if I start to type

Lon ( for london )

the list below immediately goes to L when I type L, then Lo and so on till I finally rest on London.
I did ( with forum users help ) as similar thing involving dynamic list boxes with a 2D array in JavaScript. I presume this is much more involved.

I just need some pointers i.e.
Can it be done ( I am presuming yes ), major considerations ( time, effort etc ).

Thanks in advance.

Lenin.