The WAP protocol was designed to show internet contents on wireless clients, like mobile phones.
What you should already know
Before you continue you should have a basic understanding of the following:
- WWW, HTML and the basics of building Web pages
- JavaScript
- XML
If you want to study these subjects first, before you start reading about WAP and the wireless markup language WML, you can find the tutorials you need at W3Schools' Home Page.
What is WAP?
The wireless industry came up with the idea of WAP. The point of this standard was to show internet contents on wireless clients, like mobile phones.
- WAP stands for Wireless Application Protocol
- WAP is an application communication protocol
- WAP is used to access services and information
- WAP is inherited from Internet standards
- WAP is for handheld devices such as mobile phones
- WAP is a protocol designed for micro browsers
- WAP enables the creating of web applications for mobile devices.
- WAP uses the mark-up language WML (not HTML)
- WML is defined as an XML 1.0 application
The Wireless Application Protocol
The WAP protocol is the leading standard for information services on wireless terminals like digital mobile phones.
The WAP standard is based on Internet standards (HTML, XML and TCP/IP). It consists of a WML language specification, a WMLScript specification, and a Wireless Telephony Application Interface (WTAI) specification.
WAP is published by the WAP Forum, founded in 1997 by Ericsson, Motorola, Nokia, and Unwired Planet. Forum members now represent over 90% of the global handset market, as well as leading infrastructure providers, software developers and other organizations. You can read more about the WAP forum at our WAP Forum page.
WAP Micro Browsers
To fit into a small wireless terminal, WAP uses a Micro Browser.
A Micro Browser is a small piece of software that makes minimal demands on hardware, memory and CPU. It can display information written in a restricted mark-up language called WML.
The Micro Browser can also interpret a reduced version of JavaScript called WMLScript.
What is WML?
WML stands for Wireless Markup Language. It is a mark-up language inherited from HTML, but WML is based on XML, so it is much stricter than HTML.
WML is used to create pages that can be displayed in a WAP browser. Pages in WML are called DECKS. Decks are constructed as a set of CARDS.
What is WMLScript?
WML uses WMLScript to run simple code on the client. WMLScript is a light JavaScript language. However, WML scripts are not embedded in the WML pages. WML pages only contains references to script URLs. WML scripts need to be compiled into byte code on a server before they can run in a WAP browser.
Visit our WMLScript tutorial to learn more about scripting in WML documents.
Examples of WAP use
- Checking train table information
- Ticket purchase
- Flight check in
- Viewing traffic information
- Checking weather conditions
- Looking up stock values
- Looking up phone numbers
- Looking up addresses
- Looking up sport results
FAQ about WAP
These are frequently asked question about WAP:
- What is WAP?
- Who is WAP for?
- How does WAP relate to standardization bodies?
- How is WAP related to Internet standards?
- What is the status of WAP?
- What is the future of WAP?
We will try to answer most of these questions. In the meantime read the answers at: http://www.wapforum.org/faqs/index.htm.
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.
Decks and Cards
WML pages are often called "decks". A deck contains a set of cards. A card element can contain text, markup, links, input-fields, tasks, images and more. Cards can be 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:
<?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="no1" title="Card 1"> <p>Hello World!</p> </card> <card id="no2" title="Card 2"> <p>Welcome to our WAP Tutorial!</p> </card> </wml> |
The result MIGHT look like this in your mobile phone display (note that only one card is displayed at a time):
------ Card 1 ------ Hello World! |
Paragraphs and Line Breaks
A WML card can be set up to display the paragraph and line break functions of WML:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Paragraphs"> <p> This is a paragraph </p> <p> This is another<br/>with a line break </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
------ Paragraphs ------ This is a paragraph This is another with a line break |
Text Formatting
A WML card can be set up to display the text formatting functions of WML:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Formatting"> <p> normal<br/> <em>emphasized</em><br/> <strong>strong</strong><br/> <b>bold</b><br/> <i>italic</i><br/> <u>underline</u><br/> <big>big</big><br/> <small>small</small> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display (don't take it for granted that all formatting tags will render as expected):
----- Formatting ----- normal emphasized strong bold italic underline big small |
Tables
A WML card can be set up to display the table functions of WML:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Table"> <p> <table columns="3"> <tr> <td>Cell 1</td> <td>Cell 2</td> <td>Cell 3</td> </tr> </table> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
------ Table ------ Cell 1 Cell 2 Cell 3 |
Links
A WML card can be set up to display the anchor functions of WML.
<anchor>
The <anchor> tag always has a task ("go", "prev", or "refresh") specified. The task defines what to do when the user selects the link. In this example, when the user selects the "Next page" link, the task says "go to the file test.wml":
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Anchor Tag"> <p> <anchor>Next page <go href="test.wml"/> </anchor> </p> </card> </wml> |
<a>
The <a> tag always performs a "go" task, with no variables. The example below does the same as the <anchor> tag 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 title="A Tag"> <p> <a href="test.wml">Next page</a> </p> </card> </wml> |
Image
A WML card can be set up to display an image:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Image"> <p> This is an image <img src="/images/stickman.wbmp" alt="stickman" /> in a paragraph </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
------ Image ------ This is an image |
in a paragraphNote that .wbmp is the only image type that can be displayed in a WAP browser.
Input Fields
A WML card can be set up to let a user enter information, as demonstrated in this 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 title="Input"> <p> Name: <input name="Name" size="15"/><br/> Age: <input name="Age" size="15" format="*N"/><br/> Sex: <input name="Sex" size="15"/> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
Select and Option
A WML card, can be set up to display the select and option functions of WML:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Selectable List 1"> <p> <select> <option value="htm">HTML Tutorial</option> <option value="xml">XML Tutorial</option> <option value="wap">WAP Tutorial</option> </select> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
In the example below, the result is a selectable list where the user can select more than one item:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Selectable List 2"> <p> <select multiple="true"> <option value="htm">HTML Tutorial</option> <option value="xml">XML Tutorial</option> <option value="wap">WAP Tutorial</option> </select> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
Fieldset
A WML card, can be set up to display the fieldset function of WML:
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card title="Fieldset"> <p> <fieldset title="CD Info"> Title: <input name="title" type="text"/><br/> Prize: <input name="prize" type="text"/> </fieldset> </p> </card> </wml> |
The result MIGHT look like this in your mobile phone display:
A task specifies what action to perform when an event, like entering a card or selecting a link, occurs.
Go Task
The <go> task represents the action of switching to a new card.
<?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> <anchor> Go To Test <go href="test.wml"/> </anchor> </p> </card> </wml> |
Prev Task
The <prev> task represents the action of going back to the previous card.
<?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> <anchor> Previous Page <prev/> </anchor> </p> </card> </wml> |
Refresh Task
The <refresh> task refreshes some specified card variables. If any of the variables are shown on the screen, this task also refreshes the screen.
|
The example below uses an <anchor> tag to add a "Refresh this page" link to the card. When the user clicks on the link, he or she refreshes the page and the value of the variable x will be set to 30: <?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> <anchor> Refresh this page <go href="thispage.wml"/> <refresh> <setvar name="x" value="30"/> </refresh> </anchor> </p> </card> </wml> |
Noop Task
The <noop> task says that nothing should be done (noop stands for "no operation"). This tag is used to override deck-level elements.
The <do> tag can be used to activate a task when the user clicks on a word/phrase on the screen.
|
The example below uses a <do> tag to add a "Back" link to the card. When the user clicks on the "Back" link, he or she should be taken back to the previous card. But the <noop> tag prevents this operation; when the user clicks on the "Back" link nothing will happen: <?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 name="back" type="prev" label="Back"> <noop/> </do> </p> </card> </wml> |
Task Elements
| Start tag | Purpose | WML |
|---|---|---|
| <go> |
Represents the action of switching to a new card |
1.1 |
| <noop> |
Says that nothing should be done (noop stands for "no operation"). Used to override deck-level elements |
1.1 |
| <prev> |
Represents the action of going back to the previous card |
1.1 |
| <refresh> | Refreshes some specified card variables. If any of the variables are shown on the screen, this task also refreshes the screen | 1.1 |