Wireless Markup Language

Categories: Computer stubs | Markup languages | Telephony | Wireless communications | XML

Wireless Markup Language is the primary content format for devices that implement the WAP (Wireless Application Protocol) specification based on XML, such as mobile phones. WML documents are XML documents that validate against the WML (currently version 1.1) DTD (Document Type Definition). You can use the W3C Markup Validation service (http://validator.w3.org/) to validate WML documents (they are validated against their declared document type).

For example, the following WML page could be saved as "example.wml":

 <?xml version="1.0"?>
 <!DOCTYPE wml PUBLIC "-//PHONE.COM//DTD WML 1.1//EN" "http://www.phone.com/dtd/wml11.dtd" >
 <wml>
   <card id="main" title="First Card">
     <p mode="wrap">This is a sample WML page.</p>
   </card>
 </wml>

WML pages are stored on a web server. They are accessed by a WAP gateway, which sits between mobile devices and the World Wide Web, passing pages from one to the other much like a proxy. This translates pages into a form suitable for mobiles. This process is hidden from the phone, so it may access the page in the same way as a browser accesses html, using a URL (for example http://example.com/foo.wml), if the mobile phone operator has not specifically prevented this.

Wireless Markup Language is a lot like HTML (Hyper Text Markup Language) in that it provides navigational support, data input, hyperlinks, text and image presentation, and forms. A WML document is known as a “deck”. Data in the deck is structured into one or more “cards” (pages) – each which represents a single interaction with the user. WML has a scaled down set of procedural elements which can be used by the author to control navigation to other cards.

Mobile devices are moving towards support for greater amounts of XHTML and even standard HTML as processing power in handsets increases. It is likely WML will be phased out in the future.

The Opera web browser supports WML.

There is also an extension available for the Mozilla/Firefox browsers to display WML content: http://wmlbrowser.mozdev.org/

More WML capable browsers/emulators:

WinWAP for Windows, for Pocket PC, for Windows Mobile 2003

Klondike 1.5 for Windows by Apache

Wapaka for download or online use (Java).

The only with strict WML syntax check:

Openwave phone simulator v7.0, v6.2.2 for Windows.

Online WML/WAP browsers (no need to download):

Wapsilon

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WML-generation tools: