W3C on RIA standards

The W3C Web API Working Group is chartered to develop standard APIs for client-side Web Application development. This work will include both documenting existing APIs such as XMLHttpRequest and developing new APIs in order to enable richer Web Applications.

An Excerpt;

This deliverable should be based on an existing application/UI format, such as Mozilla’s XUL, Microsoft’s XAML, Macromedia’s MXML or Laszlo Systems’ LZX, provided the owners of the format are willing to contribute. The format should allow embedded program code. This format, combined with the deliverables below and existing technologies including XHTML, CSS, XForms, SVG and SMIL, should provide a strong basis for rich client application development.