Emerging Technology: WML

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Emerging Technology WML

• Team Three Amigos

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WML Frequently Asked Questions

• What is WML?
• Stands for Wireless Markup Language
• Based on XML
• Read and interpreted within a browser (like HTML)
• Browser is built into a Wireless Application
  Prototype (WAP) device such as a cell phone
• The WAP browser is commonly called a
  micro-browser, indicating that its capabilities
  are initially somewhat limited the browsers
  capabilities are further limited due to the
  capabilities of the WAP device in which it
  operates

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WML Frequently Asked Questions

• Why is WML significant as an emerging technology?
• WAP devices are becoming increasingly powerful in
  their ability to access and transfer online
  information
• WML is the only language used in the WAP
  environment
• Requires very little bandwidth to operate
• Requires far less processing power to operate
  than does HTML, meaning longer-lasting batteries
• Is simple visually, making it more compatible
  with the small displays of cell phones, PDAs, etc.

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WML Frequently Asked Questions

• Which text editors can I use to code WML?
• Almost any text editor can be used for WML coding
• A few WML-specific editors available for free
  download, including the WAPPage and WAPtor
  editors
• It is not recommended to use What You See Is What
  You Get editors that are closely tied with HTML
  development they will not understand WML

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WML Frequently Asked Questions

• What is the syntax of WML?
• WML pages are called decks
• Decks hold cards that are related to one another
  with links
• Navigation between cards is done within the phone
  and does not require extra trips to the server
• Each WML page contains a prolog
• Following the prolog, every WML document contains
  a document tag that contains all other sub-tags
  and entities

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Example Code

• Here is the source code for a simple, one-card
  WML deck
• lt?xml version"1.0"?gtlt!DOCTYPE wml PUBLIC
  "-//WAPFORUM//DTD WML 1.1//EN" "http//www.wapforu
  m.org/DTD/wml_1.1.xml"gtltwmlgtltcard id"hey"
  title"Test"gtltp align"center"gtHello!lt/pgtlt/card
  gtlt/wmlgt

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WML Frequently Asked Questions

• What are some examples of elements found in WML?
• ltwmlgt
• This is the document tag it defines the deck
  and encloses the cards
• ltcardgt
• This is the card tag cards make up the content
  of the deck
• Syntaxltcard ((attributes))gt .....lt/cardgt
• Exampleltcard id"MyCard" title"Welcome"
  newcontexttrue" orderedtrue" gt

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WML Frequently Asked Questions

• Tag examples continued
• ltdogt
• The do tag is used to perform actions on both
  decks and cards
• Examplelt!--- If the user selects "next" they
  will be taken to the card "nextcard.wml"
  ---gt ltdo type"accept" label"next"gtltgo
  href"nextcard.wml"/gtlt/dogt
• ltimggt
• Very similar to the image tag found in HTML
• Exampleltimg srcimage.wbmp" alt"Example
  Image" hspace"1" vspace"1"/gt

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WML Frequently Asked Questions

• Tag examples continued
• ltselectgt
• Specifies a list of options to choose from
• Examplelt!--- Select an Airport --!gtltselect
  name"airport"gt   ltoptgroup title"Southeast
  Airports"gt   ltoption value"gsp"gtGSPlt/optiongt   
  ltoption value"atl"gtHartsfield-Jacksonlt/optiongt  
   ltoption value"char"gtCharlotte
  Douglaslt/optiongt   lt/optgroupgtlt/selectgt
• ltsetvargt
• Sets a variable to a specified value
• Exampleltsetvar namesomename"
  valuesomevalue"/gt

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WML Frequently Asked Questions

• How does WAP allow a cell phone or other wireless
  device to access the Internet?
• The mobile user enters the URL of the requested
  WAP site
• The phone converts the text URL to a binary WSP
  request
• The phone sends the binary WSP request to the WAP
  gateway
• The gateway converts the WSP request to an HTTP
  request
• The gateway sends the HTTP request to the
  Internet
• The Internet server creates the WML page
• The server sends the response back to the WAP
  gateway
• The gateway converts the WML to binary code
• The gateway sends the binary WML using WSP
  protocol
• The phone converts the binary WML to text WML
• The phones browser reads the WML and displays it
• Client ?? WAP Gateway/Proxy ??
  Internet

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Comparison between WML and HTML

• WML
• Markup language for wireless communication
• Makes use of variables
• WML script stored in a separate file
• Images stored as 2-bit WBMP files
• Browser used is called a micro-browser
• Case sensitive
• A set of WML cards make a deck

• HTML
• Markup language for wired communication
• Does not use variables
• JavaScript embedded into the same file
• Images stored as larger GIF, JPEG or PNG files
• Browsers used include IE, Safari, Mozilla, etc.
• Not case sensitive
• A set of HTML pages make a site

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WML Shortcomings

• WML is case sensitive, and this can be somewhat
  frustrating
• WML is VERY unforgiving to syntax errors
• WML has a very low bit rate and can therefore be
  quite sluggish
• The display is not aesthetically appealing and is
  somewhat use-limited
• In order to be seen by a WAP device, a site has
  to have a separate version of each page written
  in WML.
• New languages, including XHTML Basic, are being
  developed to counter these shortcomings
• Higher bit rate technologies, including GPRS and
  3G, may take away any future need for WML