| <!DOCTYPE html> |
| <style> |
| html, |
| body { |
| height: 100%; |
| margin: 0; |
| overflow: hidden; |
| } |
| |
| #target { |
| height: 100%; |
| width: 100%; |
| } |
| </style> |
| <div id="target"></div> |
| <script> |
| function observeViewport() { |
| return new Promise(resolve => { |
| const observer = new IntersectionObserver(([entry]) => { |
| observer.disconnect(); |
| resolve(entry.isIntersecting); |
| }); |
| observer.observe(document.querySelector('#target')); |
| }); |
| } |
| |
| function observeViewportIntersectionRatio() { |
| return new Promise(resolve => { |
| const observer = new IntersectionObserver(([entry]) => { |
| observer.disconnect(); |
| resolve(entry.intersectionRatio); |
| }); |
| observer.observe(document.querySelector('#target')); |
| }); |
| } |
| </script> |
