Assembly: System.Design (in system.design.dll)
Each ClientScriptItem object in the ClientScriptItemCollection class represents a script block that is contained in a document (a Web Form, Web server control, a content page, or a master page) at design time.
Use the WebFormsRootDesigner class to set or examine client script elements that are contained in a Web Forms document on the design surface. Retrieve the collection of client script elements that are contained within the Web document by using the GetClientScriptsInDocument method. Add a client script element to the Web document by using the AddClientScriptToDocument method.
To add client script elements at run time, use the ClientScriptManager class.
The ClientScriptItemCollection class represents script elements at design time that execute on the client. Because the script elements that are generated for ClientScriptItemCollection objects are not run on the server, the elements do not contain the runat="server" attribute.