It's unclear what you mean by 'data for species', but chances are that if Javascript is involved, then it's just an AJAX call. Use a tool like
Firebug to watch the net transactions and learn the appropriate URLs. And while you are at it, review the site terms of service and check for a robots.txt file to make sure you are scraping resepctfully.
#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.