| <!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; | 
 | } | 
 | #root { | 
 |  width: 170px; | 
 |  height: 200px; | 
 |  overflow-y: scroll; | 
 | } | 
 | #target { | 
 |  width: 100px; | 
 |  height: 100px; | 
 |  background-color: green; | 
 |  position: absolute; | 
 | } | 
 | </style> | 
 |  | 
 | <div id="root" style="position: absolute"> | 
 |  <div id="target" style="left: 50px; top: 250px"></div> | 
 | </div> | 
 |  | 
 | <script> | 
 | var entries = []; | 
 | var root, target; | 
 |  | 
 | runTestCycle(function() { | 
 |  root = document.getElementById("root"); | 
 |  assert_true(!!root, "root element exists."); | 
 |  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."); | 
 |  target.style.top = "10px"; | 
 |  runTestCycle(test1, "In containing block and intersecting."); | 
 | }, "IntersectionObserver should only report intersections if root is a containing block ancestor of target."); | 
 |  | 
 | function test1() { | 
 |  runTestCycle(test2, "In containing block and not intersecting."); | 
 |  var rootBounds = contentBounds(root); | 
 |  checkLastEntry(entries, 0, [58, 158, 18, 118, 58, 158, 18, 118].concat(rootBounds)); | 
 |  target.style.top = "250px"; | 
 | } | 
 |  | 
 | function test2() { | 
 |  runTestCycle(test3, "Not in containing block and intersecting."); | 
 |  var rootBounds = contentBounds(root); | 
 |  checkLastEntry(entries, 1, [58, 158, 258, 358, 0, 0, 0, 0].concat(rootBounds)); | 
 |  root.style.position = "static"; | 
 |  target.style.top = "10px"; | 
 | } | 
 |  | 
 | function test3() { | 
 |  runTestCycle(test4, "Not in containing block and not intersecting."); | 
 |  checkLastEntry(entries, 1); | 
 |  target.style.top = "250px"; | 
 | } | 
 |  | 
 | function test4() { | 
 |  checkLastEntry(entries, 1); | 
 |  target.style.top = "0"; | 
 | } | 
 | </script> |