A Short WML 1.1 Reference

This Wireless Markup Language (WML) reference relates to WAP WML version 1.1 from 16-Jun-1999. If possible, the equivalent HTML code is mentioned or the differences to HTML are shown up.
Compiled WML (aka WMLC), WMLScript and Wireless Bitmaps (aka WBMP) are left out.
More information can be found at: http://www.wapforum.org/

Table of Contents

• General Syntax
• Restriction on Document Size
• Document Structure
• Header Elements
• Text Elements
• Hypertext Links
• Images
• Forms
• Variables
• Tables
• Special Characters
• Reserved Tags
• Literature
• Links

General Syntax

All WML-tags are enclosed in <...>. The tag has to follow the open bracket directly without space. WML is (in comparsion to HTML) case-sensitive (<tag> is not equal to <TAG>) and all WML-tags are lower-case.

Tab, blank, carriage return and line feed are treated as spaces. One or more spaces directly before or behind a tag are ignored. Several consecutive spaces are treated as one single space.

There is a differentiation between standalone-tags and paired tags. Standalone-tags (like <tag/>) can appear everywhere in the text. Please note the trailing slash ("/"), it always appears before the closing ">". Paired tags (e.g. <tag> and </tag>; also called container) enclose text and have the form <tag>...</tag> like in HTML. Interlocked tags have to be closed in reverse order of opening, like in HTML, too: <a><b>...</b></a>

Some WML tags may occur in both forms, as standalone-tag and as paired tag. If the tag is used as standalone-tag, the slash must appear at the end of the tag, else it must appear at the beginning of the closing tag.

Attributes to tags have the same syntax as in HTML, except that standalone-tags need the trailing slash behind the attribute (e. g. <tag attribute="abc"/>).

As in HTML documents are specified by a uniform resource locator (URL):

method://server[:port]/[path/][file][#cards]
(Actually only http is allowed as method, e.g. mailto: and tel: links are not allowed.)

The only difference in comparsion to HTML is that fragment anchors -- the URL part starting with an hash mark ("#") -- refer to cards and not to reference anchors.

Restrictions in Document Size

Most emulators actually don't care about, that mobile devices may have problems storing and parsing large WML decks, so always remember, that big WML decks may properly work on every emulator you have around, but will not work on most WAP devices.

The size of WML pages is restricted to 1024 Bytes in the binary WMLC (Compiled WML) format. So if you want to test, if your pages has the right size, you have to compile it, e.g. with the wml tools by Thomas Neill.

Document Structure

A lot of the following descriptions are cited from [WML, 1999].

WML data are structured as a collection cards. A single collection of cards is referred to as a WML deck. Each card contains structured content and navigation specifications. Logically, a user navigates through a series of cards, reviews the contents of each, enters requested information, makes choices and navigates to another card or returns to the previously visited card.

Header Elements

Text Elements

The display of text in WML can be influenced by the following tags. How these tags are rendered partially depends on the user agent.

Logical formats

Physical formats

Paragraph and line formatting

Hypertext links

In comparision to HTML there are several ways to implement hyper-links. A hyper-link is splitted into two parts: Header (for specifying the kind, the link is shown) and tasks (for specifying what to or where to go).

Hyper-link header elements

Hyper-link task elements

Images

Images not yet written.

Forms

Forms are used to interrogate information that will be returned to the Server. These will be handed over to a CGI-script that processes them.

Forms not yet written.

Variables

All WML content can be parameterised, allowing the author flexibility in creating cards and decks with improved caching behaviour and better perceived interactivity. WML variables can be used in the place of string and are substituted at run-time with their current value. Only text (incl. attribute values) can be substituted, no substitution of WML-elements nor their attributes is possible. A variable is said to be set if it has a value not equal the empty string (""). WML variable names are case sensitive and can consist of one or more 7-bit ASCII letters, digits and the underscore (_). The first character of a variable name must not be a digit. WML variable are reference by a dollar sign ($) followed by the of the variable. The name may be put in parentheses.

The kind of escaping the variables value can be determined with one of three (case insensítive) modifierers, appended to the variable name with a colon (:) and parenthesized together. The three escaping modifiers are:

• noesc: No change of the value of the variable
• escape: URL-escape the value of the variable
• unesc: URL-unescape the value of the variable

Examples:
(One line always show the same variable and the same escaping method.)

• $var, $(var), $(var)_x
• $var_x, $(var_x)
• $(var:escape), $(var:E), $(var:e), $(var:eScApE)
• $(var:noesc), $(var:N), $(var:n), $(var:nOeSc)
• $(var_x:unesc), $(var_x:U), $(var_x:u), $(var_x:uNeSc)

Tables

Tables in WML are similiar to HTML 3.2 tables. The most important difference is the needed presence of a columns attribute to the <table<-element. Other difference is that nesting of tables is not allowed and that there is no special table header cell tag.

Example:

<table columns="2" align="LC"> <tr><td>Article</td> <td>Number</td></tr> <tr><td>Apples</td> <td>12</td></tr> <tr><td>Pears</td> <td>29</td></tr> </table>

Article	Number
Apples	12
Pears	29

Special Characters

Character entities not yet written.

Keywords: WML, XML, Unicode

Reserved Tags

WML reserves the use of several strings for future use. The following words are reserved:

• style

Literature

WML, 1999

Wireless Application Protocol, Wireless Markup Language Specification Version 1.1; Wireless Application Protocol Forum Ltd.; 1999; http://www.wapforum.org/

Based on the Short HTML Reference by Stephan Wiehr (lynx@fsinfo.cs.uni-sb.de) and Axel Beckert (abe@deuxchevaux.org)