Scroll and focus on textBox

Hello Guys,
I use bellow code to Scrolling and focus on txtBody in ButtonClick but it's not work, what is wrong?
protected void btnReplay_Click(object sender, EventArgs e) { //Get the reference of the clicked button. Button button = (sender as Button); //Get the command argument int CmntId = Int32.Parse(button.CommandArgument.ToString()); using (mydbEntities context = new mydbEntities()) { Comment obj = context.Comments.First(x => x.Id == CmntId); txtBody.Text = "<div id='divquote' style='border:dashed 1px #9e9c9c;margin:4px;'>" + "<span style='padding-right:5px;padding-left:5px;'>" + obj.UserId_FK + " ?? ????? " + obj.CreatedTime + " ????:" + "</span><br />" + "<blockquote>" + "<p>" + obj.Body + "&l ...