WML_presentation_minter

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13 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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Wireless Markup
Language(WML)





Topics


Introduction


Constraints


Supporting Documentation


Main Functions


Deck/Cards Design


WML Elements


Client
-

Server Access


Conclusions


Application


WML Web
-
site


Introduction


WML was formed to create the global
wireless protocol specification that works
across differing wireless network
technology types, for adoption by
appropriate industry standards bodies.

Introduction


Based on XML.


Developed by the WAP forum.


WML provides a schema for describing
data so that it can be viewed on (WAP
capable) Mobile phones and Personal
Digital Assistants.

WAP Forum


The WAP Forum is the industry
association comprising of hundreds of
members.


De
-
facto world standard for wireless
information and telephony services.


Digital mobile phones and other wireless
terminals.

WML Constraints


Small display.


Limited user input facilities.


Narrowband network connection.


Limited memory and computational
resources.

Documentation


WML specification describes WML, including its
semantics, its [XML] document type definition
(DTD) and its encoding extensions.


WML Script specification describes the scripting
language, WML Script, including its lexical and
syntactic grammar, its transfer format and a
reference byte code interpreter.


WML Script Standard Libraries describes
standard library programs including a language
library, a string library, a dialog library, a
floating
-
point library, a browser library and a
URL library.

Main Functions


Text presentation and layout.


Deck/Card organizational metaphor
-

all
information in WML is organized into a
collection of cards and decks.


Inter
-
card navigation and linking
-

WML
includes support for explicitly managing the
navigation between cards and decks.


String parameterization and state management
-

all WML decks can be parameterized, using a
state model.

Decks/Cards


Deck: A single WML document (i.e. the
elements contained within the <wml>
document element) is known as a deck.


Card: A single interaction between a user
agent and a user is known as a card.


Features


Multiple screens can be downloaded to the
client in a single retrieval.


User selections or entries can be handled
and routed to already loaded cards.


Eliminates excessive transactions with
remote servers.


Multiple cards can be split
-
up into multiple
decks. (flexibility for memory constraints)


WML Elements


Document Element:

<code><wml></code>


Deck/Card Elements: wml, card, template,
head, access, meta


Event Elements: do, ontimer,
onenterforward, onenterbackward, onpick,
onevent, postfield,

WML Elements


Tasks: go, prev, refresh, noop


Variables: setvar


User input: input, select, option, optgroup,
fieldset.


Anchors, Images, and Timers: a, anchor,
img, timer.


Text Formatting: b, p, table, tr, td.

Element Syntax



<element> element value </element>


Login Example 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 id="Login" title="Login">


<do type="accept" label="Password">


<go href="#Password"/>


</do>


<p>


UserName:



<select name="name" title="Name:">


<option value="John Doe">John Doe</option>


<option value="Paul Smith">Paul Smith</option>


<option value="Joe Dean">Joe Dean</option>


<option value="Bill Todd">Bill Todd</option>




</select>


</p>


</card>








<card id="Password" title="Password:">


<do type="accept" label="Results">


<go href="#Results"/>


</do>



<p>



Password: <input type="text" name="password"/>


</p>


</card>




<card id="Results" title="Results:">


<p>


You entered:<br/>


Name: $(name)<br/>


Password: $(password)<br/>



</p>


</card>

</wml>

Calling Server Script


Dynamically connect to remote servers opens up
every WAP device to the world of Internet
messaging, enterprise data, and e
-
commerce.


WAP gateway.


Popular server scripting tools: Java Servlets,
JavaScript, ASP, or Perl.



<go href="http://127.0.0.1/WML/Inventory.asp"
method="post"><postfield name="Items"
value="$(Items)"/>


</go>

Conclusions


Entirely new, exciting platform on which
to deploy applications.


Tradeoffs and challenges: server round
-
trips, bandwidth, and display sizes.


WAP opens the door to a new era in
application development and deployment.

HTML to WML

Conversion

V1

V2

V3

Device profile

HTML

WML

End User

Gateway

Server Side

Client Side

Rearrange

User profile

Proxy Server

WML Web
-
Sites


http://www.oasis
-
open.org/cover/wap
-
wml.html


http://www.wapforum.org/docs/copyright.
htm


http://www.wirelessdevnet.com/channels/
wap/training/wml.html