Each website has a DOM Tree.
I thought it would be interesting to see a DOM tree as a sunburst diagram.
Step 1. Copy the content of domburst.js.
Step 2. Open any website and open Google Chrome developer tools (how?)
Step 3. Paste content into the console, and press Enter. The chart should appear.
In the .gif above, Facebook warns you from copy-pasting content. That is a good advice to follow.
In this particular case, the script doesn't access your cookies, neither does it send your data anywhere.
If you are familiar with JavaScript, please feel free to verify this. The entire program is ~400 lines of code, and I hope should be straightforward to follow.