| Xiaoming Shi | 73dfa20 | 2020-03-12 11:31:35 -0700 | [diff] [blame^] | 1 | <!DOCTYPE html> |
| 2 | <meta name="viewport" content="width=device-width,initial-scale=1"> |
| 3 | <script src="/resources/testharness.js"></script> |
| 4 | <script src="/resources/testharnessreport.js"></script> |
| 5 | <script src="./resources/intersection-observer-test-utils.js"></script> |
| 6 | <style> |
| 7 | #scroller { width: 100px; height: 100px; overflow: scroll; } |
| 8 | #scroller > div { height: 800px; } |
| 9 | #target { margin-top: 25px; height: 50px; background-color: blue; } |
| 10 | </style> |
| 11 | <div id="scroller"> |
| 12 | <div> |
| 13 | <div id="target"></div> |
| 14 | </div> |
| 15 | </div> |
| 16 | |
| 17 | <script> |
| 18 | let entries = []; |
| 19 | |
| 20 | window.onload = function() { |
| 21 | runTestCycle(step2, "At initial scroll position"); |
| 22 | |
| 23 | scroller.scrollTop = 0; |
| 24 | let observer = new IntersectionObserver( |
| 25 | es => entries = entries.concat(es), |
| 26 | { threshold: 1 } |
| 27 | ); |
| 28 | observer.observe(target); |
| 29 | }; |
| 30 | |
| 31 | function step2() { |
| 32 | runTestCycle(step3, "Scrolled to half way through target element"); |
| 33 | |
| 34 | assert_equals(entries.length, 1); |
| 35 | assert_equals(entries[0].intersectionRatio, 1); |
| 36 | assert_equals(entries[0].isIntersecting, true); |
| 37 | scroller.scrollTop = 50; |
| 38 | } |
| 39 | |
| 40 | function step3() { |
| 41 | runTestCycle(step4, "Scrolled to target element completely off screen"); |
| 42 | |
| 43 | assert_equals(entries.length, 2); |
| 44 | assert_true(entries[1].intersectionRatio >= 0.5 && |
| 45 | entries[1].intersectionRatio < 1); |
| 46 | assert_equals(entries[1].isIntersecting, true); |
| 47 | scroller.scrollTop = 100; |
| 48 | } |
| 49 | |
| 50 | function step4() { |
| 51 | assert_equals(entries.length, 2); |
| 52 | } |
| 53 | </script> |
