W4 A  Hera Ffx
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W4 A  Hera Ffx W4 A Hera Ffx Presentation Transcript

  • Universidad Politécnica de Madrid School of Computing José Luis Fuertes Ricardo González Emmanuelle Gutiérrez Loïc Martínez SIDAR Foundation International Cross-Disciplinary Conference on Web Accessibility Madrid, Spain April 20-21, 2009 Hera-FFX: a Firefox add-on for semi-automatic web accessibility evaluation
  • Contents
    • Introduction
    • Features of Web Accessibility Tools
    • HERA
    • HERA-FFX
      • Design
      • Overview
      • Internal structure
      • Results of analysis
      • Evaluation process
    • Conclusions
    • Future Work
  • Introduction
    • Web accessibility evaluation
      • Complex task, requiring
        • Human expertise
        • Software support
      • Human evaluators need
        • Sound knowledge
        • Experience in web development
        • WCAG proficiency
      • Software tools should
        • Provide support for manual evaluation
        • Automate as much of the work as possible
  • Features of web accessibility tools
    • Key features of a web accessibility evaluation tool
      • Automated preliminary evaluation ( AE )
      • Support for manual entry of checkpoint results ( ME )
      • Modification of page rendering to assist checkpoint evaluation ( PM )
      • Annotated code view to assist checkpoint evaluation ( CV )
      • Evaluation of local pages ( LP )
      • Evaluation of restricted-access pages ( RA )
      • Evaluation of rendered pages ( RP )
      • Report generation ( RG )
      • Support for training ( ST )
      • Multi-session capacity ( MS )
      • Flexibility to integrate other accessibility guidelines ( FL )
  • Features of web accessibility tools
    • Comparison of free web accessibility evaluation tools
    Tool Type AE MF LP CV LP RA RP RG ST MS FL A-Checker online     Access. Check online   EvalAccess online    Foxability extension       Functional Access. Evaluator online    Hera online        Cynthia Says online   Firefox Access. Extension extension      TAW online online   TAW standalone application         Torquemada online   Total Validator online   WAVE online    WAVE Firefox toolbar extension      Web Access. Inspector application    Web Access. Self-evaluation report     
  • Features of web accessibility tools
    • Results
      • All the desirable features are covered by at least one tool
      • No one tool has all the desirable features
    • There is a need for a web accessibility evaluation tool that has
      • Strong support for manual evaluation
      • Ability to evaluate all types of web pages
      • Flexibility to incorporate new accessibility guidelines
  • HERA
    • Free on-line tool from 2003-2005
    • Developed by the Sidar Foundation
    • Support for the semi-manual evaluation of Web page accessibility
    • HERA
      • “ H ojas de E stilo para la R evisión de la A ccesibilidad”
      • “ Accessibility Evaluation Style Sheets”
    • Generates new versions of the analysed page, highlighting interesting elements
    • Strengths:
      • Minimisation of the need
        • to inspect source code
        • to directly evaluate checkpoints in the original rendering
      • Positive feedback received from users
      • Valuable tool for educational purposes
  • HERA-FFX
    • Hera-FFX Design
      • Main goals :
        • Be as usable as Hera
        • Be flexible enough to incorporate additional requirements and new standards
      • Prototype decisions :
        • Firefox add-on
        • WCAG 1.0
        • Spanish
  • HERA-FFX
    • Hera-FFX overview
    Stores guideline definition, checkpoints and tests in an XML-based configuration file Firefox loads and interprets Web pages Builds a DOM representation of the web page. It is used by Hera-FFX to perform the accessibility evaluation Performs a preliminary automatic accessibility evaluation User performs a manual accessibility evaluation Accessibility report: XHTML + CSS document containing detailed information about the status of the evaluation Saved evaluation: this XML file can divide evaluations into several sessions
  • HERA-FFX
    • Internal structure for storing the required information
    Evaluation Guideline Checkpoint Test Element DOM-Element
  • HERA-FFX
    • Test analysis results
      • Hera-FFX inspects the Web page and automatically assigns a value for each test
        • Pass : the web page passes the test
        • Fail : the web page fails the test
        • Not applicable : the test is not applicable
        • Verify : the tool cannot decide what the result is and the user is asked to run the test manually
      • The user can manually assign two more values for each test
        • Partial : the web page fails the test on a minor point
        • Unknown : the evaluator cannot decide what the result of the test should be
  • HERA-FFX
    • Results of checkpoint analysis
    verify  i / eval i = verify   i ≠ j (eval j ≠ fail  eval j ≠ partial) Condition Result  i / eval i = fail fail  i / eval i = partial   i ≠ j ( eval j ≠ fail ) partial  i / eval i = pass   i ≠ j (eval j = pass  eval j = N/A ) pass  i / eval i = N/A not applicable  i / eval i = unknown   i ≠ j ( eval j = unknown  eval j = N/A) unknown
  • HERA-FFX
    • Detailed Evaluation Process
    Current web page Manual Evaluation Support Help on Checkpoints Instructions for Evaluation Modified Page View Code View Evaluation Results Result Summary Automated Preliminary Analysis Report Generation <hmtl lang=&quot;es&quot;> <head> <title>HERA </title> </head> <body>
  • HERA-FFX
    • Automated Preliminary Analysis
      • The browser loads a page
      • Hera-FFX applies the relevant tests to evaluate each DOM-element
      • An icon on the Firefox status bar shows the progress and the final aggregated result
      • Users can get more details as a tool tip
    • Summary of Results
    HERA-FFX User can choose the navigation style:
      • Table-based
      • Guideline-based
    • General information
    • URL, configuration, date, time, number of errors, number of manual checks needed, browser…
  • HERA-FFX
    • Manual Evaluation Support
      • User interface designed to evaluate point by point according to the selected navigation style
    • Interface control: keyboard and mouse
    • Colour contrast
    • Colours and icons
    • Interface elements: relative units
  • HERA-FFX
    • Manual Evaluation Support
      • Simulated view of the modified page
        • Indicates which elements have to be inspected
    • Element fails
    • Element should be evaluated
  • HERA-FFX
    • Manual Evaluation Support
      • Generated HTML code view
        • Indicates which elements have to be inspected
    • Element fails
    • Element should be evaluated
  • HERA-FFX
    • Manual Evaluation Support
      • Visualization of the result of a call to an external service
    • W3C HTML validation service
  • Conclusions
    • Both the Sidar Foundation and the Technical University of Madrid are using Hera in their Web accessibility courses with very encouraging results
    • Hera-FFX is a Firefox add-on designed to perform a semi-automatic evaluation of web accessibility
      • Automatic preliminary evaluation
      • Provides guidance for manual evaluation
      • Includes the desirable features of a web accessibility evaluation tool
  • Conclusions
    • Hera-FFX – Hera comparison
               Hera-FFX Feature Hera Automated preliminary evaluation  Support for manual entry  Modification of page presentation  Annotated code view  Evaluation of local pages Evaluation or restricted-access pages Evaluation of rendered pages Report generation  Support for training  Multi-session capacity  Flexibility
  • Conclusions
    • Hera-FFX – Hera comparison
      • Increased efficiency
        • Each manual evaluation is automatically updated
      • Same effectiveness
        • No relevant differences
      • Increased user satisfaction
        • Users can evaluate pages that they were unable to with Hera
      • Same completeness
        • 65 WCAG 1.0 checkpoints
      • Slightly increased correctness
        • Hera-FFX inspects the rendered-page, which is closer to user experience
  • Future Work
    • Report generation in different formats
      • PDF, EARL…
    • Internationalization of the add-on
    • Update to cover the Spanish web content accessibility standard (UNE 139803:2004)
    • Update to cover WCAG 2.0
      • Already started
      • Major structural changes are needed
        • To cover principles, guidelines, success criteria, techniques and failures
        • To handle WCAG 2.0 flexibility and choose between multiple techniques to satisfy a criteria
          • Consideration of “situations” (the evaluator will have to decide which situation applies to each element)
          • Boolean technique expressions
  • Future Work
    • Develop a comprehensive stand-alone evaluation tool including workgroup tools
      • Project creation and management
      • Evaluation work distribution
      • Aggregation of results from different evaluators
      • Assessment of evaluator reliability
  • Universidad Politécnica de Madrid School of Computing José Luis Fuertes Ricardo González Emmanuelle Gutiérrez Loïc Martínez SIDAR Foundation International Cross-Disciplinary Conference on Web Accessibility Madrid, Spain April 20-21, 2009 Hera-FFX: a Firefox add-on for semi-automatic web accessibility evaluation