Execute javascript function after asp.net postback without Ajax

Page.ClientScript.RegisterStartupScript(GetType(), "ShowPopup", "showCheckOutPopIn('Livraison',556);");

ScriptManager.RegisterStartupScript(this, this.GetType(), "ShowPopup", "showCheckOutPopIn('Livraison',556);", true);

ScriptManager.RegisterStartupScript(MainUpdatePanel, typeof(string), "ShowPopup", "showCheckOutPopIn('Livraison',556);", true);

Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "script", "alert('Success!');", true);