it works in the ascx but the problem is for example you are passing this as an argument for the function example
ScriptManager.R egisterStartupS cript(this, typeof(Page), "OpenWindow","a lert('1'), "true);

try instead passing a control that is inside the updatepanel example
ScriptManager.R egisterStartupS cript(GridView1, typeof(Page), "OpenWindow","a lert('1'), "true);