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

You need to user ScriptManager class because you are register script when doing postback and using updatepanel

MSDN: ScriptManager.RegisterStartupScript

ScriptManager.RegisterStartupScript method used to add client script to a page when the control is wrapped inside an UpdatePanel.

ASPX page

CodeBehind Register StartUp Script

protected void btnPostback_Click(object sender, EventArgs e)
{
    System.Text.StringBuilder sb = new System.Text.StringBuilder();
    sb.Append(@"");

    ScriptManager.RegisterStartupScript(btnPostback,this.GetType(), "JSCR", sb.ToString(),false);

}

Detail : Add JavaScript programmatically using RegisterStartupScript during an Asynchronous postback