\documentstyle{standard}

\outputon
\begin{javascript}[\mainfileroot]
var curfile = \mainfileroot.html@l10
function cline(url, text) {
  document.write('<a href="'+url+'" target="main">'+text+'</a>')
}
\end{javascript}

\begin{document}

\script{cline("fdemo0.html#@l10", "Main")}

\end{document}