About Nested Frames Example
Framesets are deprecated in HTML but periodically used.
Example
The example has a set of nested frames. The frame elements are contained in frameset elements.
Frames
Frames are rarely used since pages have to conform to an invalid HTML approach.
The page has to have no body tag.
Make sure to inspect the page to double-check this.
The frame contents can be well form html. But the parent page with the frameset has no body.
Automated Tools
Most automated tools have commands dedicated to working with frames.
In WebDriver you would switchTo().frame(...) the frame to work with it.