A method includes loading a first document from a first document domain. The first document includes a first instruction to dynamically create a second document object and a second instruction to write script loading logic into the second document object. The first document is rendered to create a rendition, the rendering including creating, in a memory, the second document object according to the first instruction; and writing, into the second document object, the script loading logic according to the second instruction. The second document object is asynchronously rendered by executing the script loading logic to send a script loading request to a script serving domain and to receive a script from the script serving domain, the script executable to modify the content of the rendition; and executing the script to modify the content of the rendition.