From http://www.w3schools.com (Copyright Refsnes Data)

WAP Basics

WAP Homepages

WAP homepages are not very different from HTML homepages. The markup language used for WAP is WML (Wireless Markup Language). WML uses tags - just like HTML - but the syntax is stricter and conforms to the XML 1.0 standard.

WML pages have the extension *.WML, just like HTML pages have the extension *.HTML.

WML Tags

WML is mostly about text. Tags that would slow down the communication with handheld devices are not a part of the WML standard. The use of tables and images is strongly restricted.

Since WML is an XML application, all tags are case sensitive (<wml> is not the same as <WML>), and all tags must be properly closed.

WML Decks and Cards

WML pages are called DECKS. They are constructed as a set of CARDS, related to each other with links. When a WML page is accessed from a mobile phone, all the cards in the page are downloaded from the WAP server. Navigation between the cards is done by the phone computer - inside the phone - without any extra access trips to the server.

Example WML document:

<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"
"http://www.wapforum.org/DTD/wml_1.1.xml">

<wml>

<card id="HTML" title="HTML Tutorial">
<p>
Our HTML Tutorial is an award winning 
tutorial from W3Schools.
</p>
</card>

<card id="XML" title="XML Tutorial">
<p>
Our XML Tutorial is an award winning 
tutorial from W3Schools.
</p>
</card>

</wml>

As you can see from the example, the WML document is an XML document. The DOCTYPE is defined to be wml, and the DTD is accessed at www.wapforum.org/DTD/wml_1.1.xml.

The document content is inside the <wml>...</wml> tags. Each card in the document is inside <card>...</card> tags, and actual paragraphs are inside <p>...</p> tags. Each card element has an id and a title.