anchor.diff:  
   
   /// Attributes to support WAI-ARIA accessibility guidelines
  -// (values for aria- and role attributes obtained from
  -//  http://w3c.github.io/html/infrastructure.html#element-attrdef-aria-role)
   module Accessibility =
       
       // Valid role attributes
  -    let _roleAlert         = attr "role" "alert"
  -    let _roleAlertDialog   = attr "role" "alertdialog"
  -    let _roleApplication   = attr "role" "application"
  -    let _roleArticle       = attr "role" "article"
  -    let _roleBanner        = attr "role" "banner"
  -    let _roleButton        = attr "role" "button"
  -    let _roleCell          = attr "role" "cell"
  -    let _roleCheckBox      = attr "role" "checkbox"
  -    let _roleColumnHeader  = attr "role" "columnheader"
  -    let _roleComboBox      = attr "role" "combobox"
  -    let _roleComplementary = attr "role" "complementary"
  -    let _roleContentInfo   = attr "role" "contentinfo"
  -    let _roleDefinition    = attr "role" "definition"
  -    let _roleDialog        = attr "role" "dialog"
  -    let _roleDirectory     = attr "role" "directory"
  -    let _roleDocument      = attr "role" "document"
  -    let _roleFeed          = attr "role" "feed"
  -    let _roleFigure        = attr "role" "figure"
  -    let _roleForm          = attr "role" "form"
  -    let _roleGrid          = attr "role" "grid"
  -    let _roleGridCell      = attr "role" "gridcell"
  -    let _roleGroup         = attr "role" "group"
  -    let _roleHeading       = attr "role" "heading"
  -    let _roleImg           = attr "role" "img"
  -    let _roleLink          = attr "role" "link"
  -    let _roleList          = attr "role" "list"
  -    let _roleListBox       = attr "role" "listbox"
  -    let _roleListItem      = attr "role" "listitem"
  -    let _roleLog           = attr "role" "log"
  -    let _roleMain          = attr "role" "main"
  -    let _roleMarquee       = attr "role" "marquee"
  -    let _roleMath          = attr "role" "math"
  -    let _roleMenubar       = attr "role" "menubar"
  -    let _roleNavigation    = attr "role" "navigation"
  -    let _roleNone          = attr "role" "none"
  -    let _roleNote          = attr "role" "note"
  -    let _roleOption        = attr "role" "option"
  -    let _rolePresentation  = attr "role" "presentation"
  -    let _roleProgressBar   = attr "role" "progressbar"
  -    let _roleRadio         = attr "role" "radio"
  -    let _roleRadioGroup    = attr "role" "radiogroup"
  -    let _roleRegion        = attr "role" "region"
  -    let _roleRow           = attr "role" "row"
  -    let _roleRowGroup      = attr "role" "rowgroup"
  -    let _roleRowHeader     = attr "role" "rowheader"
  -    let _roleScrollBar     = attr "role" "scrollbar"
  -    let _roleSearch        = attr "role" "search"
  -    let _roleSearchBox     = attr "role" "searchbox"
  -    let _roleSeparator     = attr "role" "separator"
  -    let _roleSlider        = attr "role" "slider"
  -    let _roleSpinButton    = attr "role" "spinbutton"
  -    let _roleStatus        = attr "role" "status"
  -    let _roleSwitch        = attr "role" "switch"
  -    let _roleTab           = attr "role" "tab"
  -    let _roleTable         = attr "role" "table"
  -    let _roleTabList       = attr "role" "tablist"
  -    let _roleTabPanel      = attr "role" "tabpanel"
  -    let _roleTerm          = attr "role" "term"
  -    let _roleTextBox       = attr "role" "textbox"
  -    let _roleTimer         = attr "role" "timer"
  -    let _roleToolBar       = attr "role" "toolbar"
  -    let _roleToolTip       = attr "role" "tooltip"
  -    let _roleTree          = attr "role" "tree"
  -    let _roleTreeGrid      = attr "role" "treegrid"
  -    let _roleTreeItem      = attr "role" "treeitem"
  +    // (obtained from https://www.w3.org/TR/wai-aria/#role_definitions)
  +    let _roleAlert            = attr "role" "alert"
  +    let _roleAlertDialog      = attr "role" "alertdialog"
  +    let _roleApplication      = attr "role" "application"
  +    let _roleArticle          = attr "role" "article"
  +    let _roleBanner           = attr "role" "banner"
  +    let _roleButton           = attr "role" "button"
  +    let _roleCell             = attr "role" "cell"
  +    let _roleCheckBox         = attr "role" "checkbox"
  +    let _roleColumnHeader     = attr "role" "columnheader"
  +    let _roleComboBox         = attr "role" "combobox"
  +    let _roleComplementary    = attr "role" "complementary"
  +    let _roleContentInfo      = attr "role" "contentinfo"
  +    let _roleDefinition       = attr "role" "definition"
  +    let _roleDialog           = attr "role" "dialog"
  +    let _roleDirectory        = attr "role" "directory"
  +    let _roleDocument         = attr "role" "document"
  +    let _roleFeed             = attr "role" "feed"
  +    let _roleFigure           = attr "role" "figure"
  +    let _roleForm             = attr "role" "form"
  +    let _roleGrid             = attr "role" "grid"
  +    let _roleGridCell         = attr "role" "gridcell"
  +    let _roleGroup            = attr "role" "group"
  +    let _roleHeading          = attr "role" "heading"
  +    let _roleImg              = attr "role" "img"
  +    let _roleLink             = attr "role" "link"
  +    let _roleList             = attr "role" "list"
  +    let _roleListBox          = attr "role" "listbox"
  +    let _roleListItem         = attr "role" "listitem"
  +    let _roleLog              = attr "role" "log"
  +    let _roleMain             = attr "role" "main"
  +    let _roleMarquee          = attr "role" "marquee"
  +    let _roleMath             = attr "role" "math"
  +    let _roleMenuBar          = attr "role" "menubar"
  +    let _roleMenuItem         = attr "role" "menuitem"
  +    let _roleMenuItemCheckBox = attr "role" "menuitemcheckbox"
  +    let _roleMenuItemRadio    = attr "role" "menuitemradio"
  +    let _roleNavigation       = attr "role" "navigation"
  +    let _roleNone             = attr "role" "none"
  +    let _roleNote             = attr "role" "note"
  +    let _roleOption           = attr "role" "option"
  +    let _rolePresentation     = attr "role" "presentation"
  +    let _roleProgressBar      = attr "role" "progressbar"
  +    let _roleRadio            = attr "role" "radio"
  +    let _roleRadioGroup       = attr "role" "radiogroup"
  +    let _roleRegion           = attr "role" "region"
  +    let _roleRow              = attr "role" "row"
  +    let _roleRowGroup         = attr "role" "rowgroup"
  +    let _roleRowHeader        = attr "role" "rowheader"
  +    let _roleScrollBar        = attr "role" "scrollbar"
  +    let _roleSearch           = attr "role" "search"
  +    let _roleSearchBox        = attr "role" "searchbox"
  +    let _roleSeparator        = attr "role" "separator"
  +    let _roleSlider           = attr "role" "slider"
  +    let _roleSpinButton       = attr "role" "spinbutton"
  +    let _roleStatus           = attr "role" "status"
  +    let _roleSwitch           = attr "role" "switch"
  +    let _roleTab              = attr "role" "tab"
  +    let _roleTable            = attr "role" "table"
  +    let _roleTabList          = attr "role" "tablist"
  +    let _roleTabPanel         = attr "role" "tabpanel"
  +    let _roleTerm             = attr "role" "term"
  +    let _roleTextBox          = attr "role" "textbox"
  +    let _roleTimer            = attr "role" "timer"
  +    let _roleToolBar          = attr "role" "toolbar"
  +    let _roleToolTip          = attr "role" "tooltip"
  +    let _roleTree             = attr "role" "tree"
  +    let _roleTreeGrid         = attr "role" "treegrid"
  +    let _roleTreeItem         = attr "role" "treeitem"
       
       // Valid aria attributes
  +    // (obtained from https://www.w3.org/TR/wai-aria/#state_prop_def)
       let _ariaActiveDescendant = attr "aria-activedescendant"
       let _ariaAtomic           = attr "aria-atomic"
       let _ariaAutocomplete     = attr "aria-autocomplete"
  
positive.code:     let _ariaLabelledBy       = attr "aria-labeledby"
      let _ariaLevel            = attr "aria-level"
      let _ariaLive             = attr "aria-live"
      let _ariaMultiline        = attr "aria-multiline"
      let _ariaMultiSelectable  = attr "aria-multiselectable"
      let _ariaOrientation      = attr "aria-orientation"
  
negative.code:     let _ariaCurrent          = attr "aria-current"
      let _ariaDescribedBy      = attr "aria-describedby"
      let _ariaDetails          = attr "aria-details"
      let _ariaDisabled         = attr "aria-disabled"
      let _ariaDropEffect       = attr "aria-dropeffect"
      let _ariaErrorMessage     = attr "aria-errormessage"
  