How will an update panel help in this case?

UPDATE: I have tried placing the button in the update panel but nothing happens. Firebug shows that the onclick is not fired.

I am working on a website using Google maps apiv3. I have a button through which I execute some logic using code behind of button_click and a javascript function. I am able to execute all the logic well but ultimately at the end the page reloads and I end up with nothing on the map.

<asp:Button ID="Button1" runat="server" style="z-index: 1; left: 573px; top: 146px; position: absolute" 
        Text="Show route" onclick="Button1_Click1"/>

Button_Click1:

protected void Button1_Click1(object sender, EventArgs e)
{
    using (con = new MySqlConnection("server=localhost; uid=root;password=aaa;database=Gmaps"))
    da = new MySqlDataAdapter("select * from routes where uid='a1'", con);
    da.Fill(ds, "mroute");
    foreach (DataRow r in ds.Tables[0].Rows)
    {
        uroute.Add(r["latlng"].ToString());
    }
    croute = new string[uroute.Count];
    croute = uroute.ToArray();
    hdncroute.Value = string.Join("&", croute);
    ClientScript.RegisterStartupScript(GetType(), "Javascript", "javascript:droute();", true);
}

Javascript:

function droute()
{
    var route=[];
    var temp;
    temp = document.getElementById('<%= hdncroute.ClientID %>').value;
    route= temp.split('&');
    //Loop to add locations and draw line
    var path= polyline.getPath();
    for(var i=0;i<route.length;i++)
        {
            var input= route[i];
            var ltln = input.split(",",2);
            var lat=parseFloat(ltln[0]);
            var lng=parseFloat(ltln[1]);
            var pos= new google.maps.LatLng(lat,lng);
            var marker= new google.maps.Marker({position:pos,map:map});
            path.push(route[i]);
            google.maps.event.addListener(marker,'click',showiwindow);
        }
    function showiwindow(event)
    {
    iwindow.setContent("<b>Coordinates are:</b><br/>Latitude:"+event.latLng.lat()+"<br/>Longitude:"+event.latLng.lng());
    iwindow.open(map,this);
    } 
}

Not much to bother about the logic in the code since its all fine. Only thing is I need to avoid this reload.