RMarkdown ioslides - Slide number does not show in browser
It's a security error in Chrome.
One workaround is to build the slides, then do either:
Rscript -e 'servr::httd()' -p9999or
python -m SimpleHTTPServer 9999 in the directory of the slide HTML file then browse to http://localhost:9999/test.html.
That should show the #'s and avoid the security error issue until the RStudio folks can find a way to adapt the HTML to meet Chrome's security requirements.
NOTE that this was fixed on October 1, 2015 - https://github.com/rstudio/rmarkdown/commit/718e101d8bc095e50d25170ae0a9804c2dd1b18e (thus this workaround is no longer needed if you use what is now the github version but will soon be the CRAN version of rmarkdown).