Architecture that facilitates the creation of a customized document with embedded or linked code that can be run on a client or a server without invoking the host application. A programming model makes it transparent to the code whether it is running on the client or the server. The programming model automatically “scales” to provide more features while running the document on the client and fewer features when running on the server. A transparent data island is automatically generated for the customized document that is embedded in the document and can be edited while requiring only a subset of all components of the host application to be running. A data binding mechanism is provided wherein changes that are made to the transparent data island while the host is not running can be moved back into the host document content when the document is reopened by the full host application.