Live update (XMLHttpRequest) to update 3 dependent lists (<select>)

I'm having 3 list that represents a hierarchy of data for user 
selection, eg. country, state, street name. When the user changes the 
country, the state list and street name list should refresh 
accordingly, and when the state is changed, the street name list should 
refresh accordingly. The structure is:
<select country/>
<div stateAndStreetName>
        <select state/>
        <select streetName/>
</div>

If I change the state immediately. The road name list refreshes 
properly. But if I change the country followed by the state, the street 
name list does not change. The reason is that after the state list is 
refreshed, the onchange handler is not set, ie. the <script> contents 
is not run. Has anyone done something this, or have any idea how to 
solve this? thanks.
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HweeBoon
MotionObj
(65) 6764-9774