A method and apparatus for securely displaying and communicating trusted and untrusted internet content via a web browser is described. In a preferred embodiment, the invention is an electronic marketplace system in which auction-related content is displayed in one window of a customer's web browser while item-related content is displayed in a second window of the customer's web browser, such that the auction-related content and the item-related content are substantially prevented from substantially interacting. The invention further provides a method and apparatus for communicating predetermined information between multiple documents opened in multiple web browser windows, where the documents are served from multiple domains.