Many wireless markup languages are in use today, including HDML, WML, cHTML, HTML, and XHTML. Even though HDML is still supported by many North American devices, it is recommended that you use WML or XHTML for new development. This is because WAP 1.x is based on WML, while WAP 2.x, along with other wireless Internet standards, have moved to XHTML. For wireless applications, there are two specific forms of XHTML of interest: XHTML Basic and XHTML Mobile Profile. Several technologies can be used for dynamic content generation. Some of these, such as CGI with Perl and Java servlets, are code-driven; others, such as JSPs and ASPs are page-driven. In addition, a template approach can be taken using XML with XSL stylesheets.
The next chapter provides an overview of wireless Internet technologies and the vendor products that are available.