WAP AND WML SIMPLIFIED

The WAP protocol was designed to show internet contents on wireless clients, like mobile phones.
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What You Should Already Know
Before you continue you should have a basic understanding of the following:
HTML
JavaScript
XML
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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

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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.


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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.


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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.


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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.


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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

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WAP Simplification
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WAP is an open international standard for application layer network communications in a wireless communication environment. Its main use is to enable access to the Internet (HTTP) from a mobile phone or PDA.

A WAP browser provides all of the basic services of a computer based web browser but simplified to operate within the restrictions of a mobile phone, such as its smaller view screen. WAP sites are websites written in, or dynamically converted to, WML (Wireless Markup Language) and accessed via the WAP browser.

Before the introduction of WAP, service providers had extremely limited opportunities to offer interactive data services. Interactive data applications are required to support now commonplace activities such as:

Email by mobile phone
Tracking of stock market prices
Sports results
News headlines
Music downloads



Another lesson on WAP
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The original WAP was a simple platform for access to web-like WML services and e-mail using mobile phones in Europe and the SE Asian regions and continues today with a considerable user base. The later versions of WAP were primarily for the United States region and was designed for a different requirement - to enable full web XHTML access using mobile devices with a higher specification and cost, and with a higher degree of software complexity.

There has been considerable discussion about whether the WAP protocol design was appropriate. Some have suggested that the bandwidth-sparing simple interface of Gopher would be a better match for mobile phones and Personal digital assistants (PDAs).

The initial design of WAP was specifically aimed at protocol independence across a range of different protocols (SMS, IP over PPP over a circuit switched bearer, IP over GPRS, etc). This has led to a protocol considerably more complex than an approach directly over IP might have caused.

Most controversial, especially for many from the IP side, was the design of WAP over IP. WAP's transmission layer protocol, WTP, uses its own retransmission mechanisms over UDP to attempt to solve the problem of inadequacy using TCP over high packet loss networks.



WML BASICS
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Wireless Markup Language
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Evolution of mobile web standardsWireless Markup Language, based on XML, is a markup language intended for devices that implement the Wireless Application Protocol (WAP) specification, such as mobile phones, and preceded the use of other markup languages now used with WAP, such as XHTML and even standard HTML (which are gaining in popularity as processing power in mobile devices increases).

Contents
1 WML history
2 WML markup
3 Criticism
4 References
5 See also
6 External links



WML history
Building on Openwave's HDML, Nokia's "Tagged Text Markup Language" (TTML) and Ericsson's proprietary markup language for mobile content, the WAP Forum created the WML 1.1 standard in 1998[1]. WML 2.0 was specified in 2001[2] , but has not been widely adopted. It was an attempt at bridging WML and XHTML Basic before the WAP 2.0 spec was finalized [3]. In the end, XHTML Mobile Profile became the markup language used in WAP 2.0. The newest WML version in active use is 1.3.


WML markup
WML documents are XML documents that validate against the WML DTD (Document Type Definition)[4] . The W3C Markup Validation service (http://validator.w3.org/) can be used to validate WML documents (they are validated against their declared document type).
Wireless Markup Language is a lot like HTML (Hyper Text Markup Language) in that it provides navigational support, data input, hyperlinks, text and image presentation, and forms. A WML document is known as a “deck”. Data in the deck is structured into one or more “cards” (pages) – each of which represents a single interaction with the user. The introduction of the terms "deck" and "card" into the internet and mobile phone communities was a result of the user interface software and its interaction with wireless communications services having to comply with the requirements of the laws of two or more nations.[citation needed]

WML decks are stored on an ordinary web server trivially configured to serve the text/vnd.wap.wml MIME type in addition to plain HTML and variants. The WML cards when requested by a device are accessed by a bridge WAP gateway, which sits between mobile devices and the World Wide Web, passing pages from one to the other much like a proxy. The gateways send the WML pages on in a form suitable for mobile device reception (WAP Binary XML). This process is hidden from the phone, so it may access the page in the same way as a browser accesses HTML, using a URL (for example, http://example.com/foo.wml). (Provided the mobile phone operator has not specifically locked the phone to prevent access of user-specified URLs.)

WML has a scaled down set of procedural elements which can be used by the author to control navigation to other cards.

It is an error and misconception to think of WML as a pinhole view of the Internet. The real power and value of WML is that it provides an interface for the phone hardware to initiate a call based on web content requested by user query. Consider a service that lets you enter a zip code, and obtain a list of clickable phone numbers of pizza parlors and taxicabs in your immediate location:

Mobile devices are moving towards support for greater amounts of XHTML and even standard HTML as processing power in handsets increases. These standards are concerned with formatting and presentation. They do not however address cell-phone or mobile device hardware interfacing in the same way as WML.