With reference of these article.

How to hide ( remove ) .ASPX extension in URL in ASP.Net

Calling ASP.Net WebMethod using jQuery AJAX

Here on Customers.aspx page i have used this functionality to get the page web method method to be called when the link is clicked.

 url: '<%= Page.ResolveUrl("~/Customers.aspx/GetCurrentTime")%>',

I have change the GridView column and added some Script in Customers.aspx;

HTML

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" ItemStyle-Width="30" />
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
        <%--<asp:HyperLinkField Text="View" DataNavigateUrlFormatString="~/Customers/{0}" DataNavigateUrlFields="Id" />--%>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:HyperLink ID="lnkView" runat="server" Text="View" NavigateUrl="#" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

JavaScript

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $('[id*=lnkView]').click(function () {
            debugger;
            var name = $(this).parents().closest('tr').find('td:nth-child(2)').html();
            $.ajax({
                type: "POST",
                url: '<%= Page.ResolveUrl("~/Customers.aspx/GetCurrentTime")%>',
                data: '{name: "' + name + '" }',
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: OnSuccess,
                failure: function (response) {
                    alert(response.d);
                }
            });

        });
        function OnSuccess(response) {
            alert(response.d);
        }
    });
</script>

C#

[System.Web.Services.WebMethod]
public static string GetCurrentTime(string name)
{
    return "Hello " + name + Environment.NewLine + "The Current Time is: "
        + DateTime.Now.ToString();
}