XHTML Basic to replace CHTML and WML
A fundamental problem for developers who want to create mobile versions of their Web sites is that they currently have to format their pages in HTML for desktop browsing, in Wireless Markup Language (WML) for WAP devices, and in Compact HTML (CHTML) for iMode devices. This has led to a new industry devoted to converting existing Web sites into WML or CHTML. WML is based on XML, and replaces the near-obsolete Handheld Device Markup Language (HDML), while CHTML is based on HTML. Although these markup languages are similar, the differences between them prevent a Web page from being viewable by both WAP and iMode devices. XHTML Basic will be understood by all devices and will be a universal markup language.
The complete XHTML Basic specification (see Resources) is available in English in several formats, including HTML, plain text, PostScript, and PDF. You can expect an inevitable push to replace languages like HDML and WML with XHTML Basic. However, it's important to remember that WML and HDML also define actions as well as content. These currently have no equivalent in XHTML. So, in the short term at least, WML and HDML aren't going to disappear. It will be interesting to see who wins out in the end. Plan on supporting all three markup languages at some point.
Future work in XHTML
One aspect of XHTML that's still under construction is device profiling, also known as Composite Capability Preference Profiles (CCPP). CCPP allows a device such as a cell phone to identify itself to a Web server, describe its limitations, and download only the information that it's capable of displaying. CCPP works because XHTML documents can be split into modules that can be downloaded separately.
The W3C is working on CCPP in collaboration with the WAP Forum, among others. In the summer of 2001, work began on XHTML 2.0, the final step on the bridge between HTML and XML. XHTML 2.0 is forward-looking with its incorporation of XML technologies such as XLink, XPointer, XPath, and XInclude -- all of which are currently in development or recently released by the W3C (see the roadmap in Resources).