footnoteref.sty

    \makeatletter

    \DeclareCiteCommand{\superfootcite}[\cbx@superscript]
      {\usebibmacro{cite:init}%
       \let\multicitedelim=\supercitedelim
       \iffieldundef{prenote}
         {}
         {\BibliographyWarning{Ignoring prenote argument}}%
       \iffieldundef{postnote}
         {}
         {\BibliographyWarning{Ignoring postnote argument}}}
      {\usebibmacro{citeindex}%
       \usebibmacro{cite:superfoot}%
       \usebibmacro{cite:comp}}
      {}
      {\usebibmacro{cite:dump}}

    \AtDataInput{%
      \csnumgdef{cbx@instcount@curr@\thefield{entrykey}}{0}}
    \AtEveryCitekey{%
      \csnumgdef{cbx@instcount@last@\thefield{entrykey}}{%
        \csuse{cbx@instcount@curr@\thefield{entrykey}}}%
      \csnumgdef{cbx@instcount@curr@\thefield{entrykey}}{\value{instcount}}}

    \def\iflastciteonsamepage{%
      \ifsamepage
        {\number\csuse{cbx@instcount@curr@\thefield{entrykey}}}
        {\number\csuse{cbx@instcount@last@\thefield{entrykey}}}}

    \newbibmacro*{cite:superfoot}{% 
      \iflastciteonsamepage   
        {}
        {\xappto\cbx@citehook{%
           \noexpand\footnotetext[\thefield{labelnumber}]{%
             \fullcite{\thefield{entrykey}}\addperiod}}}}


    \newrobustcmd{\cbx@superscript}[1]{%
      \mkbibsuperscript{#1}%
      \cbx@citehook
      \global\let\cbx@citehook=\empty}
    \let\cbx@citehook=\empty

    \makeatother