OK - the Javascript has converted the web page to PDF, so it's like having downloaded a PDF document from the web. If you briefly touch the resulting webpage/PDF you'll see a menu bar at the top briefly appear with the option to 'Open in' and then some options, depending on what you've got on your iPad - usually at least iBooks.
The Javascript works fine with these recipe pages - I've tried it - but it's not totally foolproof because it has to reload the page to do the conversion.
So, if it's a page into which you've entered some text in text boxes, that text might not appear in the PDF. Effectively, the PDF you get is what the webpage would look like if you refreshed the page.
So, to recap, you're not doing anything wrong. It looks as though the Javascript is working fine because it's converted the recipe to an identical looking PDF. So, just touch the page and see if you can spot the menu bar open up at the top of the page with those options.
If there's any remaining problem, just get back to me (I'm out for the next hour though)
Tim