bung 6 œ Netzbasierte Informationssysteme Accessibility(Mobile) Dr. Lyndon J B Nixon FreieUniversität Berlin Institut für Informatik Netzbasierte Informationssysteme mailto: [email protected] http://page.mi.fu-berlin.de/nixon Zeitplan Aufgabe Übungsblatt Abgabe Präsentationen 1. Website 23. Okt 30. Okt 31. Okt 2. Suche 6. Nov 13. Nov 20. Nov 3. Crawler 20. Nov 27. Nov 28. Nov 4. Web 2.0 4. Dez 11. Dez 12. Dez 5. Internation- 18. Dez 8. Jan 11. Jan alisierung 6. Accessibility 15. Jan 22. Jan 23. Jan 7. Metadata 29. Jan 5. Feb 6. Feb AG Netzbasierte Informationssysteme http://www.ag-nbi.de 2 Übung 6 • Übungsblatt 6 ist online auf der Website der Veranstaltung http://www.ag-nbi.de/lehre/0708/V_NBI/ • Thema: Accessibility • Aufgabe: Website zugänglich über Handy machen • Heute haben wir diesen Struktur • Rückblick: The Mobile Web • Hintergrund: Mobile Standards • Hintergrund: Serving Mobile Content • Aufgabe: Website für Mobilgeräte anpassen • Aufgabe: Website prüfen AG Netzbasierte Informationssysteme http://www.ag-nbi.de 3 Mobile Web: ups and downs Courtesy http://www.w3.org/2006/Talks/0419-MWI-Analysts AG Netzbasierte Informationssysteme http://www.ag-nbi.de 4 Mobile Web: the beginnings • HDML • originally developed in about 1996 by the company that becameOpenwave. It was replaced by WML. • WAP • WAP was hyped at the time of its introduction, leading users to expect WAP to havethe performanceof the Web • In terms of speed, easeof use, appearance, and interoperability, the reality fellfar short of expectations. This led to the wideusageof sardonicphrases such as "Worthless Application Protocol", "Wait And Pay", and so on. • WML cut users off from the HTML Web tyingthem to a smallselection of native WAP content or converted Web- to-WAPcontent • Devices had limited capabilities and werepoorly profiled AG Netzbasierte Informationssysteme http://www.ag-nbi.de 5 Mobile Web: the deathof WAP • The wireless carriers killed WAP however • Didn”t support the production of WAP content • Charged users by the data accessed, discouragingsurfing • Offerings werea ‚walled garden—, often withthe carrier”s own portalas homepageand availablecontent restricted to what other sites the carrier madedeals with AG Netzbasierte Informationssysteme http://www.ag-nbi.de 6 Mobile Web: enter i-mode • launched in Japan on 22 February 1999 • i-modeborrows from fixed Internet data formats such as C-HTML based on HTML in constrast to WAP/WML • It becamea runaway success becauseof the well- designed services and business model, as well as the strongdemand for mobile emailservices whicharepart of i-mode. • As of June30, 2006, i-modehas 46.8 million customers in Japan and over 5 million in the rest of the world AG Netzbasierte Informationssysteme http://www.ag-nbi.de 7 Mobile Web: i-mode, a fallingstar • Telstra (Australia) and O2 (United Kingdom) on the 18th of July 2007, announced that they weredropping support for i-modeservices. • KPN (Netherlands) on the 19th of July 2007, announced that it will no longer belaunchingnew i-modeservices or mobile phones geared towards i-modesupport. • Citinglow subscriber numbers • Compact HTML has been overtaken by the more standards friendly XHTML, promoted by the W3C and Open Media Alliance • The iModebusiness modelcan not competewithan open, non-restricted Web access modelbeingoffered by carriers today AG Netzbasierte Informationssysteme http://www.ag-nbi.de 8 Mobile Web: towards open standards • Open Mobile Alliance launched June2002 as an answer to the proliferation of industry forums eachdealingwith a few application protocols • W3C launched Mobile Web Initiative withheavy industry support AG Netzbasierte Informationssysteme http://www.ag-nbi.de 9 Mobile Web: what changed? • Rapid evolution of capabilities of mobile phones • 1.1 billion Web-capablemobile phones worldwideœ 63% of all handsets (Informa, 2005) • Growinguseof Internet on the mobile device Source: Nokia study, 2005 Browsingis the Number One data packet generating service AG Netzbasierte Informationssysteme http://www.ag-nbi.de 10 Mobile Web = mobile browsers • Opera Mini • Two million users • Four million web pages per day • 38 to 76 Gbdata trafficdaily (Opera, April 2006) AG Netzbasierte Informationssysteme http://www.ag-nbi.de 11 Mobile Web: growth potential • 74% of Web capablephones not used to access the Web (Informa, 2005) • W3C has set up the Mobile Web Initiative (MWI) to promotemobile deviceaccess to the Web • Requirement: solvethe usability problem • Mobile Web Best Practices • ‚mobileOK— trustmarkfor content • Requirement: providedeviceinformation • Currently expensive(devicemanufacturer databases) or buggy (user generated databases) • MWI workingon a Shared Repository • Requirement: agreeon standards for Web content • See next! AG Netzbasierte Informationssysteme http://www.ag-nbi.de 12 Mobile Standards • A number of specificmarkuplanguages specified for the Mobile Web led to initialconfusion and poor uptake • Wireless MarkupLanguage(WML) • Handheld DeviceMarkupLanguage(HDML) • Compact HTML (cHTML) -> was used by iModephones • Thanks to W3C efforts, XHTML Basic is emergingas the standard for Web content on mobile phones. As a simplified version of HTML 4.0 • Non-modified Web sites can still bedisplayed, although they will potentially bepoorly organised or navigable • Web sites can bemoreeasily modified to support the XHTML Basic subset AG Netzbasierte Informationssysteme http://www.ag-nbi.de 13 Mobile Standards: WML / WAP 1.0 • Wireless MarkupLanguage(WML) • WML content is delivered by a normal HTTP server like Apache • Delivery mechanism is known as Wireless Application Protocol(WAP) • A gateway deviceis positioned between the phoneand the server whichacts likea proxy • The gateway takes a request from the phoneand fetches the WML pagefrom the server • The WML pageis binary encoded and passed to the phone(to minimisebandwidthand enablephone companies to monitor usage) • WML 1.0 supported monochrome and limited layout AG Netzbasierte Informationssysteme http://www.ag-nbi.de 14 Mobile Standards: WAP 2.0 • WML/WAP 1.0 was tied to the limitations of bandwidth and display encountered by mobile phones • As the hardwareevolved, the specification was superceded and the WAP Forum moved to supportinga subset of XHTML for Mobile Phones (XHTML MP) • XHTML MP is a superset of XHTML Basic which, along withCSS, has been approved by the WAP Forum as the markup languagefor mobile Web content • The delivery mechanism also evolved to WAP 2.0 • XHTML MP content is passed directly to the phone without binary encoding • The roleof the gateway is reduced to monitoringusage AG Netzbasierte Informationssysteme http://www.ag-nbi.de 15 Mobile Standards: XHTML • Convert your HTML 4.0 documents to XHTML 1.0 using the followingsteps: • makesurethat all your tags arenested correctly ie. ifyouput a bold tag and then italic, closethe italic beforeyouclosethe bold: <b><i>bold and italic</i></b> • convert all your tags to lowercase XHTML is case-sensitive • includeall end tags, and closesingleton tags ie. <p></p> and <br /> • quoteall your attributes ie. <imgsrc="image" /> AG Netzbasierte Informationssysteme http://www.ag-nbi.de 16 Mobile Standards: XHTML Basic • Makesureyour XHTML does not includeany elements not part of the followingmodules: • StructureModule body, head, html, title • Text Module abbr, acronym, address, blockquote, br, cite, code, dfn, div, em, h1, h2, h3, h4, h5, h6, kbd, p, pre, q, samp, span, strong, var • Hypertext Module a • List Module dl, dt, dd, ol, ul, li • Basic Forms Module form, input, label, select, option, textarea • Basic Tables Module caption, table, td, th, tr • Image Module img • Object Module object, param • Meta Information Module meta • Link Module link • Base Module base AG Netzbasierte Informationssysteme http://www.ag-nbi.de 17 Mobile Standards: XHTML Basic • What youdefinitely shouldn”t have • style element Ifyouneed to useCSS, youshould useexternalstyle sheets withthe link element • script and noscript elements most smalldevices havelimited memory, and scripting may not besupported • frames frames depend upon a screen interfacethat may or may not bepresent in a smalldevice AG Netzbasierte Informationssysteme http://www.ag-nbi.de 18 Mobile Standards: XHTML MP • derived from XHTML 1.1 Basic Profile by addingXHTML Modules • later versions of the standard added moremodules. • However, for certain modules, XHTML-MP does not mandatea completeimplementation so a XHTML-MP browser may not befully conformingon all modules. • The MIMEtypefor XHTML Mobile Profile is "application/vnd.wap.xhtml+xml". Conforminguser agents should also accept "application/xhtml+xml" and "text/html". AG Netzbasierte Informationssysteme http://www.ag-nbi.de 19 Mobile Standards: XHTML MP <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd" > <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Cafe</title> </head> <body> <p align="center" style="color: red;"> <img src="cafe.gif" alt="cafe"/><br/> <b>Rob's Transport Cafe</b> </p> <p align="center"> Greasy food cooked to perfection, then cooked some more </p> <p align="center"> <a href="cafe_menu.xhtml" accesskey="1" title="Menu">Menu</a> <a href="cafe_location.xhtml" accesskey="2" title="Location">Location</a> </p> </body> </html> AG Netzbasierte Informationssysteme http://www.ag-nbi.de 20 Mobile Standards: XHTML MP This XHTML MP pagewill looksomethinglikethis: Two differences to regular XHTML: 1. Required DOCTYPE identifyingcontent