Problem while implementing cascade select option in Struts2 [City/Locality/Streets]

I am trying to implement a select drop down for City, Locality, Street. Once I select City, Locality values should change automatically. Once I select Locality, streets values should change automatically.

Here is the html code. I am using struts2 and taking values from database using hibernate. Things are working fine. Except for onchange="" I need to implement.

<s:form id="FormName" namespace="/namespacename"
						action="ActionName" method="post">

</div></td>
								</tr>
								<tr>
									<td><div class="input-container">
											<s:select label="Locality" name="locality" id="locality"
												headerKey="1" headerValue="Select Locality "
												list="localities" listKey="localityid"
												listValue="localityname" />

</div></td>
								</tr>
<tr>
									<td><div class="input-container">
											<s:select label="Street" name="street" id="street"
												headerKey="1" headerValue="Select Street " list="streets"
												listKey="streetid" listValue="streetname" />

</div></td>
								</tr>
	</tbody>
						</table>

</s:form>

Here I have found a similar thread but could not get much: how to populate a list in a another select tag using a select tag using struts 2 & DOJO (ajax)

Please help me implement the onchange="". Thanks in advance.