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Understand WML Chao-Hsien Chu, Ph.D. School of Information Sciences and Technology The Pennsylvania State University Possible Service Types by WAP Local Development Services Messaging Call Handling WAP Information Services Gamming Electronic Commerce Transport Database Access
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Understand WML Chao-Hsien Chu, Ph.D. School of Information Sciences and Technology The Pennsylvania State University
Possible Service Types by WAP Local Development Services Messaging Call Handling WAP Information Services Gamming Electronic Commerce Transport Database Access
Physical Devices: Size / Display Memory / Cache Size Battery Data Entry Methods Contents: Different Standards Micro browser Scarcity of contents Block internet surfing. Character-based Info. Networks: Bandwidth limitations. Incomplete service coverage. Lack of an installed user base. High customer cost. Changing communications standards. Latency Connection reliability Security. Limitations of Wireless
Why New Standard Telecom services Info services Unified mailbox E-mail Info Call control Security Message Services WWW ITTP HDML Other SIM toolkit TTML WAP
WSP/WTP HTTP WAP Client WAP Gateway Web Server WML WMLScript WTAI WML Interpreter WML Encoder WML Script Compiler Protocol Bearers CGI Scripts (PERL, ASP, Java) WML and WMLScript Contents Internet WAP Architecture
Sketch of WAP Network Architecture WAP gateway Web server Corporate Firewall Filter HTML WML WAP gateway Wireless Network Web server WTA server
HTML JavaScript Application Layer (WAE) Other Services and Applications HTTP Session Layer (WSP) Transaction Layer (WTP) TLS-SSL Security Layer (WTLS) TCP/IP UDP/IP Transport Layer (WPD) Bearers SMS USSD CSD IS-136 CDMA CDPD PDC Etc. Internet Protocol vs. WAP
Application Layer Other Services And Applications Session Layer Transaction Layer Security Layer Transport Layer (WPD) Bearers SMS USSD CSD IS-136 CDMA CDPD PDC Etc. Wireless Application Protocol
WML Structure • Deck - File • Card – Screen • Head: XML, DTD Declarations • Template: <template>, </template> • Root Element: <wml>, </wml> • Card: <card>, </card>
WML Structure Process Instruction <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN" "http://www.wapforum.org/DTD/wml12.dtd"> <wml> <template> … </template> <card> <p> … </p> </card> </wml> Document Type Declaration Root Element Template Cards
WML’s Functionality • Text Presentation and Layout: text formatting, line breaks, and alignment. • Images – Wireless Bitmap (WBMP) and image alignment. • User Inputs – Choice lists, multilevel choices, text entry, and task controls. • Cards and Deck Organization. • Navigation – URL Naming and anchored links, between cards in a deck, between decks. • State and Context Management – Variable passing between decks, Cache both variables and decks.
<p> </p> Two attributes: align = “left”, “center” or “right” mode = ‘wrap” or “nowrap” Paragraph
Navigation between Cards and Decks • <a> … </a> • <anchor> … </anchor>
Events • <onenterforward>: Invoke a card via a GO statement. • <onenterbackward>: Navigate to a card via the <prev> statement. • <onpick>: Select an option. • <ontimer>: Delay time for action. • These events are invoked via an <onevent> element, an <option> element, or as part of a <template> or <card> element.
Example of Do Element <do type=“options” label=“titles” name=“titles”> <go href=“#titles”/> </do> <do type=“options” label=“Authors” name=“authors”> <go href=“#authors”/> </do> <do type=“options” label=“Books” name=“books”> <go href=“#booklist”/> </do>
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