anchor.diff:  Contains a few asciidoc files to show
   typical semantic errors in html files 
   which kbd:[HtmlSC] checker will detect and report.
  -
  -[small]#last update {docdate}, build with Asciidoctor {asciidoctor-version}#
   
   toc::[]
   
  
positive.code: . broken link targets in map (broken href in area-tag)
  
  
  [[missing-alt-attributes]]
  === Missing Alt-Attributes (in Image-Tags)
  TODO
negative.code: <3> areas on the image together with the respective link targets.
  
  
  *Several things could go wrong with ImageMaps*
  
  . referenced map does not exist (wrong usemap or wrong map-name)
  . several maps exists with same name (ambiguous map-name)
  