GoogleMaps API Calculate distance between two places for a particular country using JavaScript

Hi guys, By referring to the following URL i able to return distance between two places. http://www.aspsnippets.com/Articles/Google-Maps-V3-API-Calculate-distance-between-two-addresses-points-locations.aspx 1) May i know how can i show Malaysia only places in Pickup & Destination textbox? 2) I tried to change it from html to aspx. May i know how i can return distance value to label (.net component)

Pickup:
<asp:TextBox ID="txtSource" runat="server" Width="400"></asp:TextBox>
&nbsp; Destination:
<asp:TextBox ID="txtDestination" runat="server" Width="400"></asp:TextBox>
&nbsp;
<asp:Button ID="btnSubmit" runat="server" Text="Get Route" OnClientClick="GetRoute()" />