The cause of the problem is clear: If you look at the sources of https://cran.r-project.org/web/packages/metap/refman/metap.html
you will see repeated instances of <script id="MathJax-script" async src="../../mathjaxr/doc/mathjax/es5/tex-chtml-full.js"></script> which is invalid HTML. I am not sure where this is coming from, because a recent update to mathjaxr should have fixed this, and \mathjaxr is now supposed to produce something different: https://github.com/cran/mathjaxr/blob/master/man/macros/mathjax.Rd#L5 Could be that versions are still catching up, so maybe wait a few days. Best, -Deepayan On Wed, 17 Dec 2025 at 20:21, Michael Dewey <[email protected]> wrote: > > I use the mathjaxr package to disply the formulae in my package. It has > been working for some while including in R 4.2.2. However when I checked > a new version of the package (metap) in r-devel I get a Note which starts > > * checking HTML version of manual ... NOTE > Found the following HTML validation problems: > metap.html:553:1 (dat.metap.Rd:18): Warning: <script> anchor > "MathJax-script" already defined > > and then carries on with the same warning for each .Rd file. The > relevant line is where it loads mathjax. > > At the moment this is only a NOTE so I could either try my luck > explaining to CRAN or change every instance of mathemtical formulae in > every .Rd file. I am reluctant to do either of them until I understand > what is happening. A possible clue might be in the NEWS for r-release > > The HTML help system has several new features: LaTeX-like math can be > typeset using either KaTeX or MathJax, usage and example code is > highlighted using Prism, and for dynamic help the output of examples and > demos can be shown within the browser if the knitr package is installed. > These features can be disabled by setting the environment variable > _R_HELP_ENABLE_ENHANCED_HTML_ to a false value. > > So the new message might be coming from that new check. > > Does anyone know what the explanation is or can offer advice aboud my > way forward? > > -- > Michael Dewey > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-package-devel ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
