| <!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> | 
 | pre, #log { | 
 |   position: absolute; | 
 |   top: 0; | 
 |   left: 200px; | 
 | } | 
 | #root { | 
 |   width: 200px; | 
 |   height: 200px; | 
 |   overflow: visible; | 
 | } | 
 | #target { | 
 |   background-color: green; | 
 | } | 
 | </style> | 
 |  | 
 | <div id="root"> | 
 |   <div id="target" style="width: 100px; height: 100px; transform: translateY(250px)"></div> | 
 | </div> | 
 |  | 
 | <script> | 
 | var entries = []; | 
 |  | 
 | runTestCycle(function() { | 
 |   var root = document.getElementById('root'); | 
 |   assert_true(!!root, "root element exists."); | 
 |   var target = document.getElementById('target'); | 
 |   assert_true(!!target, "target element exists."); | 
 |   var observer = new IntersectionObserver(function(changes) { | 
 |     entries = entries.concat(changes); | 
 |   }, { root: root }); | 
 |   observer.observe(target); | 
 |   entries = entries.concat(observer.takeRecords()); | 
 |   assert_equals(entries.length, 0, "No initial notifications."); | 
 |   runTestCycle(step0, "First rAF."); | 
 | }, "IntersectionObserver should detect and report edge-adjacent and zero-area intersections."); | 
 |  | 
 | function step0() { | 
 |   runTestCycle(step1, "Set transform=translateY(200px) on target."); | 
 |   checkLastEntry(entries, 0, [8, 108, 258, 358, 0, 0, 0, 0, 8, 208, 8, 208, false]); | 
 |   target.style.transform = "translateY(200px)"; | 
 | } | 
 |  | 
 | function step1() { | 
 |   runTestCycle(step2, "Set transform=translateY(201px) on target."); | 
 |   checkLastEntry(entries, 1, [8, 108, 208, 308, 8, 108, 208, 208, 8, 208, 8, 208, true]); | 
 |   target.style.transform = "translateY(201px)"; | 
 | } | 
 |  | 
 | function step2() { | 
 |   runTestCycle(step3, "Set transform=translateY(185px) on target."); | 
 |   checkLastEntry(entries, 2); | 
 |   target.style.height = "0px"; | 
 |   target.style.width = "300px"; | 
 |   target.style.transform = "translateY(185px)"; | 
 | } | 
 |  | 
 | function step3() { | 
 |   checkLastEntry(entries, 3, [8, 308, 193, 193, 8, 208, 193, 193, 8, 208, 8, 208, true]); | 
 | } | 
 | </script> |