GeoMap在更新面板内部无效

<script src="Scripts/jquery-1.3.2.min.js" type="text/javascript"></script>
<script type='text/javascript' src='http://www.google.com/jsapi'></script>
<script src='http://maps.google.com/maps?file=api&v=2&key=ABCDEFG' type='text/javascript'></script>
<script type='text/javascript'>

google.load('visualization', '1', { 'packages': ['geomap'], 'language': 'fr'});        

    var countryCode;

    function DrawWorldMap(country, lat, lang, name, count, usercount, user, bandwidth, vtitle, htitle, title1, title2) {
        try {
            var data = new google.visualization.DataTable();
            data.addRows(count);
            data.addColumn('string', 'Country');
            data.addColumn('number', 'BandWidth');
            var contry = country.split(',');
            var band = bandwidth.split(',');

            for (var i = 0; i < count; i++) {
                data.setValue(i, 0, contry[i]);
            }
            for (var h = 0; h < count; h++) {
                data.setValue(h, 1, Number(band[h]));
            }
            var options = {};
            options['dataMode'] = 'regions';

            var container = document.getElementById('<%=map_canvas.ClientID%>');
            var geomap = new google.visualization.GeoMap(container);
            geomap.draw(data, options);
            var lati = lat;
            var langi = lang;
            var loop = count;
            google.visualization.events.addListener(
    geomap, 'regionClick', function (e) {
        countryCode = e['region'];
        CreateCountryMap(lati, langi, name, loop, usercount, country, user, bandwidth, vtitle, htitle, title1, title2);

    });

        }            
        catch (exception) {
            alert('drawworldmap: ' + exception);
        } 
        drawVisualization(user, bandwidth, usercount, vtitle, htitle, title1, title2); // here am calling the chart function..
    }

   function drawVisualization(User, Bandwidth, counts, vtitle, htitle, title1, title2) {
        try {
            // Create and populate the data table.
            var data = new google.visualization.DataTable();
            data.addColumn('string', title1);
            data.addColumn('number', title2);
            var username = User.split(',');
            var BandWidth = Bandwidth.split(',');
            for (var i = 0; i < counts; i++) {
                data.addRow([String(username[i]), Number(BandWidth[i])]);
            }

            // Create and draw the visualization.
            new google.visualization.LineChart(document.getElementById('<%=visualization.ClientID%>')).
        draw(data, { curveType: "function", pointSize: 5, title: 'User Chart', titlePosition: 'out',
            width: 400, height: 350, backgroundColor: 'AliceBlue',
            vAxis: { maxValue: 100, title: vtitle }, fontSize: 8, hAxis: { title: htitle }
        }
            );
        }
        catch (exception) {
            alert(exception);
        }
    }       

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>

<asp:DropDownList ID="ddlusername" runat="server" AutoPostBack="true" 
        OnSelectedIndexChanged="ddlusername_SelectedIndexChanged" Height="17px" 
        Width="132px">   </asp:DropDownList>    

<div id="visualization" align="center" style="border: thin solid grey;" runat="server"> </div>

<div id='map_canvas' style="border: thin solid grey;" align="center" runat="server"> </div>

<asp:Label ID="lblmap" runat="server"></asp:Label>

</ContentTemplate>
</asp:UpdatePanel>

   ScriptManager.RegisterStartupScript(lblmap, this.GetType(), "js2", "google.setOnLoadCallback(DrawWorldMap('" + contry + "','" + city + "','" + langitude + "','" + longitude + "'," + count + "," + usercount + ",'" + username + "','" + bandwidth + "','Bandwidth','UserName','User','BandWidth'));", true);