RegisterStartupScript doesn't work with ScriptManager,Updatepanel. Why is that?

Question

protected void timer1_Tick(object sender, EventArgs e)
    {
        foreach (RepeaterItem item in rpChat.Items)
        {
            TextBox txt = item.FindControl         


        

Answer 1

In my case ScriptManager.RegisterStartupScript didn't work too.

Not work:

ScriptManager.RegisterStartupScript(Me, 
  Me.GetType(), 
  String.Format("Data{0}", Me.ID), 
  "", 
  False)

Work:

ScriptManager.RegisterStartupScript(Me.Page, 
  Me.GetType(), 
  String.Format("Data{0}", Me.ID), 
  "", 
  False)

Me in the example is my custom control inherited from System.Web.UI.WebControls.WebParts.WebPart