int  initHTML(char ***mime_types, int *nrtypes, float **prefs);
  int  openHTML(const W3ADocumentInfo doc,  Widget  workarea, long id);
  int  infoHTML(long id, W3ADocumentInfo *info);
 int writeHTML(long id, const char *buf, size_t nbytes);
  int  closeHTML(long id);
 void eventHTML(long id, long source, long eventtype, void *params);