| <!DOCTYPE html> | 
 | <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; | 
 | } | 
 | .spacer { | 
 |   height: calc(100vh + 100px); | 
 | } | 
 | #target { | 
 |   width: 100px; | 
 |   height: 100px; | 
 |   background-color: green; | 
 | } | 
 | </style> | 
 |  | 
 | <div class="spacer"></div> | 
 | <div id="target"></div> | 
 | <div class="spacer"></div> | 
 |  | 
 | <script> | 
 | var vw = document.documentElement.clientWidth; | 
 | var vh = document.documentElement.clientHeight; | 
 |  | 
 | var entries = []; | 
 | var target; | 
 |  | 
 | runTestCycle(function() { | 
 |   target = document.getElementById("target"); | 
 |   assert_true(!!target, "target exists"); | 
 |   var observer = new IntersectionObserver(function(changes) { | 
 |     entries = entries.concat(changes) | 
 |   }); | 
 |   observer.observe(target); | 
 |   entries = entries.concat(observer.takeRecords()); | 
 |   assert_equals(entries.length, 0, "No initial notifications."); | 
 |   runTestCycle(step0, "First rAF."); | 
 | }, "IntersectionObserver in a single document using the implicit root."); | 
 |  | 
 | function step0() { | 
 |   document.scrollingElement.scrollTop = 300; | 
 |   runTestCycle(step1, "document.scrollingElement.scrollTop = 300"); | 
 |   checkLastEntry(entries, 0, [8, 108, vh + 108, vh + 208, 0, 0, 0, 0, 0, vw, 0, vh, false]); | 
 | } | 
 |  | 
 | function step1() { | 
 |   document.scrollingElement.scrollTop = 100; | 
 |   runTestCycle(step2, "document.scrollingElement.scrollTop = 100"); | 
 |   checkLastEntry(entries, 1, [8, 108, vh - 192, vh - 92, 8, 108, vh - 192, vh - 92, 0, vw, 0, vh, true]); | 
 | } | 
 |  | 
 | function step2() { | 
 |   document.scrollingElement.scrollTop = 0; | 
 |   checkLastEntry(entries, 2, [8, 108, vh + 8, vh + 108, 0, 0, 0, 0, 0, vw, 0, vh, false]); | 
 | } | 
 | </script> |