Expanding List Web Components example

This example is from mdn: using custom elements

Click on (some) list elements to expand them

• UK
  • Yorkshire
    • Leeds
      • Train station
      • Town hall
      • Headrow
    • Bradford
    • Hull
• USA
  • California
    • Los Angeles
    • San Francisco
    • Berkeley
  • Nevada
  • Oregon

• This list is not expandable
• So this and the next item...
• Are always visible.