It looks like the 10K API call offer is limited to people who sign up for the developer plan ($149/mo), but your post implies it's free. Did I misread the offer in your post?
Ahah, great ! The minimum required version is 10.10 (Yosemite)
If you want to do that on the web, you'll have to render the page in an iframe to select the content and most websites don't allow it. In short, the user experience is way better with a software.