knitr
package in R. I have knitr listed under LaTeX, but actually, you could use a simpler process called markdown to create a "reproducible research" document on the web. See this blog. There is play on words in the name markdown, which creates HTML pages (hyper text markup language). Oh, and LaTeX is also a markup language. To get bold text in LaTeX you do this:
{\bf This text will be bold.}
Whereas in HTML it looks like this:
< b > This text will be bold. < /b >In each case you use special marks to say "start bold" and "stop bold".