Asp Control ASP.Net

<%@ Page Language="C#" %>

    protected void btnDelete_Click(object sender, EventArgs e)
    {
        lblResult.Text = "All pages deleted!";
    }



    Button OnClientClick


    
    

    
            id="btnDelete"
        Text="Delete Website"
        OnClick="btnDelete_Click"
        OnClientClick="return confirm('Are you sure?');" 
        Runat="server" />
    
            id="lblResult"
        Runat="server" />