Wireless Markup Language (WML)

CS4984 - Prof. Abrams

1. Purpose of WML
2. System View: Delivering WML via Internet
3. WML Syntax and Examples
4. Exercises
5. References

1. Purpose of WML

Target of WML

Developers of apps for wireless devices

Typical Devices

Phones
PDAs

Typical Device Characteristics

Small display

Limited input capability

Narrowband network connection

Limited memory

Limited CPU power

2. System View: Delivering WML via Internet

The normal web delivery of pages to HTML browsers looks like this (from [AEO]:

A gateway is used to do a protocol conversion when a doc is delivered from an origin server to a phone. A protocol conversion also occurs (to use a compact binary version of HTTP).

What phones have WML browsers?

Click here to find out!

3. WML Syntax and Examples

Document Model

Controls text presentation and layout

User interface is deck of cards

Deck = HTML page

User navigates through sequence of cards

WML file is prameterized -- instantiate with variables to save memory

Provides inter-card navigation and linking

Supports scriting

Event handling for navigation or script invocation

User Navigation Model

Browser maintans stack of URLs giving history, just like web browser
Three operations on stack:

Reset: Set stack to contain current card only
Push: Put new URL on stack
Pop: Remove current URL; return to previous URL

The Prev button on the phone does a pop.

First Example

<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"
   "http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card>
    <p>
      <do type="accept">
        <go href="#card2"/>
      </do>
    Hello!
    This is the first card...
    </p>
</card>
<card id="card2">
    <p>
    This is the second card.
    Goodbye!
    </p>
</card>
</wml>

Try this in a phone simulator to see what results!

More Examples

Try out the other examples in the Unwired Planet\UPSDKW32\examples\wml file.

4. Exercises

How to run the Unwired Planet phone simulator:

Select Start->Programs->UP.SDK3.2forWML->UP.Simulator
In the "go" bar type something like this:

file:\\c:/program files/unwired planet/upsdkw32/examples/wml/controls.wml

You can also chose File->Open configuration to change the style of phone

5. References

[WML] Wireless Application Protocol Wireless Markup Language Specification Version 1.1, Version 16-June 1999, http://www1.wapforum.org/what/technical/SPEC-WML-19990616.pdf
[AEO] Wireless Application Proocol Wireless Application Environment Overview, Version 16-June-1999, http://www1.wapforum.org/what/technical/SPEC-WAEOverview-19990616.pdf
Unwired Planet's phone and WML browser simulator, available from dev.phone.com.

Last modified on 15 September 1999 by abrams@vt.edu