Ajax ASP.Net Tutorial

<%@ Page Language="C#" %>
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

    protected void btnDeleteAll_Click(object sender, EventArgs e)    {
        if (FileHelper.DeleteAll() == true)
        {
            string script = @"alert('All Files Deleted Successfully!');";
            Page.ClientScript.RegisterStartupScript(this.GetType(), "filesDeleted", script, true);
        }
    }



    Show Alert


    
    

            id="btnDeleteAll"
        Text="Delete All Files"
        OnClick="btnDeleteAll_Click"
        Runat="server" />