Introduction to WML
At last we arrive at the nitty-gritty of wireless applications—WML. This section should give you a flavor of how WML works, but it falls far short of a complete education. For more information, refer to one of the complete resources listed at the end of this chapter. The complete set of WML elements and attributes is summarized in the following section.
Document Structure
Because of the unique viewing environment on handheld devices, the
whole notion of the “page” and page-based design as they
are thought of in HTML is abandoned. WML applications use a
“card” metaphor instead. An application is made up of one
or more decks
(.wml documents), each containing some number of
cards
(WML elements defined within a
document). A card contains a limited amount of information, equal to
just a few screenfuls where a screen holds only three to six lines of
text.
Because WML is an application of XML (see Chapter 30), WML documents need to be both valid (using WML elements properly according to the DTD) and well-formed (abiding by the stringent rules of XML markup syntax).
The following is a very simple WML document called
jenskitchen.wml. It is a “deck”
containing two “cards.”
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN" "http://www.wapforum.org/DTD/wml_1.2.xml"> <wml> <card id="intro"> <p>Welcome to Jen's Cookbook Nook</p> </card> <card id="book1"> <p>101 Things to Do with Wild Mushrooms</p> <p>Jennifer Niederst</p> <p>Price: $19.95</p> </card> ...
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