Validate at least one checkbox checked Validation for CheckBox inside Repeater in ASP.Net

HTML

  <asp:Repeater ID="Repeater1" runat="server">
        <HeaderTemplate>
            <table id = "tblContacts" border="0" cellpadding="0" cellspacing="0">
                <tr>
                    <th>
                    </th>
                    <th>
                        Name
                    </th>
                    <th>
                        Country
                    </th>
                </tr>
        </HeaderTemplate>
        <ItemTemplate>
            <tr>
                <td>
                    <asp:CheckBox Text="" runat="server" />
                </td>
                <td>
                    <%#Eval("Name") %>
                </td>
                <td>
                    <%#Eval("Country") %>
                </td>
            </tr>
        </ItemTemplate>
        <FooterTemplate>
            </table>
        </FooterTemplate>
    </asp:Repeater>
    <br />
    <asp:Button Text="Submit" runat="server" OnClientClick = "return Validate();" />
    <script type = "text/javascript">
        function Validate() {
            var table = document.getElementById("tblContacts");
            var checkboxes = table.getElementsByTagName("input");
            for (var i = 0; i < checkboxes.length; i++) {
                if (checkboxes[i].type == "checkbox" && checkboxes[i].checked) {
                    return true;
                }
            }
            alert("Please select at least one record!");
            return false;
        }
    </script>

Code

  protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[3] { new DataColumn("Id", typeof(int)),
                            new DataColumn("Name", typeof(string)),
                            new DataColumn("Country",typeof(string)) });
            dt.Rows.Add(1, "John Hammond", "United States");
            dt.Rows.Add(2, "Mudassar Khan", "India");
            dt.Rows.Add(3, "Suzanne Mathews", "France");
            dt.Rows.Add(4, "Robert Schidner", "Russia");
            Repeater1.DataSource = dt;
            Repeater1.DataBind();
        }
    }

Namespace

using System.Data;