ScriptManager does not get updated after AsyncPostBackTrigger happened and AsyncPostBack happened

Question

i am creating a different script at every postback whether Async or not and i am registering it with this code

inside pageload

  ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "deneme",srJavaScript, true);

but the problem is page is only executing first time registered script after AsyncPostBack

i really need help to solve this problem i am trying to maintaince div scroll position after AsyncPostBacks