|  | <!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: 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> |