Call web service to get data

i have a web service at this url http://196.218.16.133/onlinereservation/service.asmx?op=HotelsSearch

i use hotel search file with HotelSearch method and method will retrieve xml file contains the matched data.

the varialbe that i made post with it is named : HotelData

the data of the variable is a string file that contains an xml data like this

<HotelsParameters>	
<CityID>388</CityID>
<UserName>admin</UserName>	
<UserPassword>admin</UserPassword>	
<DateFrom>4/12/2010</DateFrom>	
<DateTo>4/13/2010</DateTo>	
<NumberOfRooms>2</NumberOfRooms>	
<Room>		
<RoomSerial>1</RoomSerial>		
<Adults>1</Adults>		
<Child>			
<ChildSerial>1</ChildSerial>			
<ChildAge>5</ChildAge>		
</Child>	
</Room>	
<Room>		
<RoomSerial>2</RoomSerial>		
<Adults>2</Adults>		
<Child>			
<ChildSerial>1</ChildSerial>			
<ChildAge>8</ChildAge>		
</Child>	
</Room>	
<Room>		
<RoomSerial>3</RoomSerial>		
<Adults>3</Adults>		
<Child>		
</Child>	
</Room>	
<CurrencyID>162</CurrencyID>
</HotelsParameters>

i am trying to get the result by posting HotelData but i did not get the xml result file
so can anyone help me
my code is:


        <script language="JavaScript">
            function InitializeService() {
                service.useService("http://196.218.16.133/onlinereservation/service.asmx?WSDL", "HotelsSearch");
            }
            var StrSearch;
            function GetAge() {
                StrSearch = document.DemoForm.StringSearch.value;

                service.HotelsSearchService.callService("HotelsSearch", StrYear);
            }
            function ShowResult() {
                alert(event.result.value);
            }
    </script>
        <form name="DemoForm">
            Hotel Name : <input type="text" name="HotelData"/><br />
            <button onclick="GetAge()">Get Age</button><br />
        </form>


the data in input filed is the previous xml file