The URL reference to the resource.
At run time, the ClientScriptManager.GetWebResourceUrl(Type, string) method returns a URL to a resource. The System.Web.Handlers.AssemblyResourceLoader class defines the HTTP handler that is used to load embedded resources.
At design time, the ClientScriptManager.GetWebResourceUrl(Type, string) method of the System.Web.UI.ClientScriptManager class detects design mode and delegates to the designer-host service implementation, which returns a URL.