Why should I care about Cross-Origin Resource Sharing and Inter-Document (iFrame) messaging?
W3C Cross-Origin Resource Sharing reduces the need for portals. Previously, portals were invented because of the single-origin security constraint of the Web; applications could only connect to servers that served up the application, for example, their origin. Web servers had to connect and aggregate information from a variety of Web sources in order to present them to the user on one Web page. This was primarily for security reasons (for example, to avoid cross-site attacks). HTML 5 has addressed this issue. Aggregation can now occur on the browser without the need for portals and portal farms. Inter-Document messaging allows Web developers to easily create Web application integration known as “mashups” on the browser. For example, one user can click on a particular company in a list of stocks in a portfolio application. The click could trigger a message to another document (iFrame) to retrieve and present the most up-to-date research report about that company.
