>can anyone tell me if it is possible and if so 
>then how to download this page:
>http://www.laits.utexas.edu/tex/gr/pro9.html 
>recursively with the links to and the content of 
>the sound files (those speaker icons) using httrack?
Forget about the javascript completely.
The makers of the website anticipated this problem.
Their web pages include the solution already. Each
contains a link in the top-left-hand corner, to
a zip-file that contains all the sound files for
that page. For example,

<http://www.laits.utexas.edu/tex/zip/pro9.zip>

contains all the media files for the page

<http://www.laits.utexas.edu/tex/gr/pro9.html>,

and 

<http://www.laits.utexas.edu/tex/zip/pro8.zip>

contains all the media files for 

<http://www.laits.utexas.edu/tex/gr/pro8.html>

and so on. This suggests you should add +*.zip
to your "Scan Rules" settings and 

zip <--> application/x-zip

to your "MIME types" settings