Assessment of Web Accessibility and Technical Specifications Conformance of Web Sites from Four EU Member States Carmen Marincu, BEng Submitted for qualification of: PhD Supervisor: Dr. Barry McMullin School of Electronic Engineering Dublin City University Dublin, Ireland I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of PhD is entirely my own work and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. Signed: ID No: 50162292 UfrftiHaU Date: 16/01/2006 Contents 1 Introduction 1 1.1 Web accessibility.................................................................................. 1 1.2 Web accessibility in the E U .................................................................. 2 1.3 Thesis overview ...................................................................................... 2 2 Background Information 6 2.1 Chapter Overview ................................................................................... 6 2.2 The World Wide W eb ............................................................................ 7 2.3 The Web and People with Disab ilities................................................ 12 2.3.1 B lindness................................................................................... 15 2.3.2 Visual im p airm en t.................................................................. 20 2.3.3 Mobility impairments ............................................................ 23 2.3.4 Deafness and hard of hearing.................................................. 24 2.3.5 Cognitive and neurological disability .................................. 25 2.3.6 Web Accessibility ................................................................... 28 2.4 W3C’s Web Content Accessibility Guidelines 1 .0 .......................... 34 2.4.1 O verview ................................................................................... 34 2.4.2 WCAG—The Future (WCAG 2.0)......................................... 37 2.5 Web Accessibility P o lic ie s ................................................................... 39 2.6 Chapter Sum m ary................................................................................... 46 1 3 Web Accessibility Survey 47 3.1 Chapter Overview ................................................................................. 47 3.2 The survey objectives........................................................................... 48 3.2.1 Evaluation of web accessibility levels on samples of web s ite s ............................................................................................ 48 3.2.2 Implementation of automated web accessibility surveying system ...................................................................................... 50 3.3 Related w o r k ........................................................................................ 51 3.4 Chapter Summary................................................................................. 60 4 Methodology 61 4.1 Chapter Overview .................................................................................. 61 4.2 Sampling methodology........................................................................ 63 4.2.1 Subjective sampling methodology of the Irish web space . 64 4.2.2 Automated random sampling methodology of the Irish, UK, German and French web spaces.................................... 67 4.3 Mirroring tool........................................................................................ 76 4.4 WCAG conformance evaluation to o l ................................................. 79 4.5 HTML technical conformance evaluation to o l ................................. 85 4.6 The automated surveying system ........................................................ 96 4.6.1 Implementation of data gathering s t a g e .............................. 96 4.6.1.1 Gathering overall process information ............. 96 4.6.1.2 Gathering mirroring process information .... 101 4.6.1.3 Gathering WCAG 1.0 conformance investiga­ tion information 103 4.6.1.4 Gathering HTML technical conformance inves­ tigation information ................................................. 106 4.6.2 Implementation of data reporting stage ................................. 108 2 4.6.2.1 Reporting web content mirroring process infor­ mation ........................................................................ 110 4.6.2.2 Reporting WCAG 1.0 conformance investiga­ tion information............................................. I l l 4.6.2.3 Reporting HTML technical conformance inves­ tigation information 112 4.7 Chapter Summary......................................................................................114 5 Web accessibility guidelines and HTML technical conformance tests 115 5.1 Chapter Overview ...................................................................................... 115 5.2 Bobby Priority 1 diagnostics...................................................................116 5.2.1 g9: Provide alternative text for all im a g e s ..............................116 5.2.2 g240: Provide alternative text for all image map hot-spots (A R E A s)..................................................................................... 120 5.2.3 glO: Provide alternative text for all image-type buttons in f o r m s .........................................................................................123 5.2.4 g39: Give each frame a t i t l e ....................................................124 5.2.5 g38: Each FRAME must reference an HTML file 126 5.2.6 g21: Provide alternative text for each A PPLET .................... 127 5.2.7 g20: Provide alternative text for each O B JEC T .................... 128 5.3 Bobby Priority 2 diagnostics...................................................................129 5.3.1 g 104: Use relative sizing and positioning (percent values) rather than absolute (pixels).....................................................129 5.3.2 g271: Use a public text identifier in a DOCTYPE statement 130 5.3.3 g265: Do not use the same link phrase more than once when the links point to different U R Ls.................................... 131 5.3.4 g269: Make sure event handlers do not require use of a m ouse............................................................................................133 3 5.3.5 g41: Explicitly associate form controls and their labels with the LABEL elem ent...........................................................133 5.3.6 g34: Create link phrases that make sense when read out of co n tex t.................................................................................. 134 5.3.7 g2: Nest headings properly........................................................135 5.3.8 g273: Include a document T IT L E .......................................... 135 5.3.9 g37: Provide a NOFRAMES section when using FRAMES 136 5.3.10 g5: Avoid scrolling text created with the MARQUEE ele­ ment ............................................................................................136 5.3.11 g4: Avoid blinking text created with the BLINK element . 137 5.3.12 g254: Do not cause a page to redirect to a new URL . 138 5.3.13 g33: Do not cause a page to refresh automatically 138 5.4 OpenSP diagnostics..................................................................................139 5.4.1 Missing or unusable DOCTYPE declaration..........................141 5.4.2 Undefined attribute (OpenSP diagnostic ID 108) ................ 141 5.4.3 Element not allowed by the document type (OpenSP di­ agnostic ID 6 4 ) ........................................................................... 142 5.4.4 Required attribute not specified (OpenSP diagnostic ID 127) 143 5.4.5 End tag for element not opened (OpenSP diagnostic ID 79) 143 5.4.6 Missing required end tag (OpenSP diagnostic ID 68) . 144 5.4.7 Non SGML character number (OpenSP diagnostic ID 139) 144 5.4.8 General entity not defined and no default entity (OpenSP diagnostic ID 2 5 ) ........................................................................ 145 5.4.9 Attribute value not allowed (OpenSP diagnostic ID 131) . 146 5.4.10 End tag for element not finished (OpenSP diagnostic ID 73) 146 5.4.11 Attribute value must be literal (OpenSP diagnostic ID 82) 146 5.5 Chapter O verview..................................................................................... 147 4 6 Analysis of web accessibility evaluation results of Irish, UK, French and German web samples - December 2004 148 6.1 Chapter Overview ......................................................................................148 6.2 Analysis of web content mirroring process results........................... 151 6.3 Analysis of WCAG 1.0 conformance investigation results................. 155 6.3.1 Key r e s u lts ................................................................................... 155 6.3.2 Bobby completion data ............................................................... 156 6.3.3 Bobby Priority 1 diagnostics......................................................157 6.3.4 Bobby Priority 2 diagnostics......................................................162 6.4 Analysis of HTML technical conformance investigation results . 168 6.4.1 Key r e s u lts ................................................................................... 168 6.4.2 OpenSP completion d ata ............................................................ 168