i use ScriptManager.RegisterClientScriptInclude to include js file after partial postback it works fine here : ** ScriptManager.RegisterClientScriptInclude(this, typeof(test4), "1", Page.ResolveClientUrl("~/slideshow/js/slideshow.js")); ** but i want to load more than one js files so i did this ** ScriptManager.RegisterClientScriptInclude(this,typeof(test4),"one", Page.ResolveClientUrl("~/slideshow/js/slideshow.js")); ScriptManager.RegisterClientScriptInclude(this, typeof(test4), "two", Page.ResolveClientUrl("~/slideshow/js/slideImg.js")); ** with two different string keys the first one works but the second not....please any help