| <!DOCTYPE html> |
| <meta name="viewport" content="width=device-width,initial-scale=1"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="./resources/intersection-observer-test-utils.js"></script> |
| <style> |
| #scroller { width: 100px; height: 100px; overflow: scroll; } |
| #scroller > div { height: 800px; } |
| #target { margin-top: 25px; height: 50px; background-color: blue; } |
| </style> |
| <div id="scroller"> |
| <div> |
| <div id="target"></div> |
| </div> |
| </div> |
| |
| <script> |
| let entries = []; |
| |
| window.onload = function() { |
| runTestCycle(step2, "At initial scroll position"); |
| |
| scroller.scrollTop = 0; |
| let observer = new IntersectionObserver( |
| es => entries = entries.concat(es), |
| { threshold: 1 } |
| ); |
| observer.observe(target); |
| }; |
| |
| function step2() { |
| runTestCycle(step3, "Scrolled to half way through target element"); |
| |
| assert_equals(entries.length, 1); |
| assert_equals(entries[0].intersectionRatio, 1); |
| assert_equals(entries[0].isIntersecting, true); |
| scroller.scrollTop = 50; |
| } |
| |
| function step3() { |
| runTestCycle(step4, "Scrolled to target element completely off screen"); |
| |
| assert_equals(entries.length, 2); |
| assert_true(entries[1].intersectionRatio >= 0.5 && |
| entries[1].intersectionRatio < 1); |
| // See https://github.com/w3c/IntersectionObserver/issues/432 |
| assert_equals(entries[1].isIntersecting, false); |
| scroller.scrollTop = 100; |
| } |
| |
| function step4() { |
| assert_equals(entries.length, 2); |
| } |
| </script> |
