_spFormOnSubmitCalled is set to
true. SharePoint uses this variable to check if a submit was executed and prevents any further submits. Since your “download postback” does not refresh the page this variable remains
true. With the effect that all other buttons stop working. In SharePoint 2013 there is a function for resetting _spFormOnSubmitCalled to false already so no need to write your own.
here is my code
SPList list = webObj.Lists["Documents"]; SPFile file = list.RootFolder.Files["your pdf file url"]; Response.ContentType = "Application/pdf"; Response.AppendHeader("content-disposition", "attachment; filename=" + file); Response.Clear(); Response.Flush(); Response.End();
after writing this code just add the below lineyour client side code.
Hope this help