<!DOCTYPE html> <meta name="viewport" content="width=device-width,initial-scale=1"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <div id="root"></div> <script> test(function() { var observer = new IntersectionObserver(function(e) {}, {}); test(function() { assert_equals(observer.root, null) }, "observer.root"); test(function() { assert_array_equals(observer.thresholds, [0]) }, "observer.thresholds"); test(function() { assert_equals(observer.rootMargin, "0px 0px 0px 0px") }, "observer.rootMargin"); observer = new IntersectionObserver(function(e) {}, { rootMargin: " ", threshold: [] }); test(function() { assert_array_equals(observer.thresholds, [0]) }, "empty observer.thresholds"); test(function() { assert_equals(observer.rootMargin, "0px 0px 0px 0px") }, "whitespace observer.rootMargin"); var rootDiv = document.getElementById("root"); observer = new IntersectionObserver(function(e) {}, { root: rootDiv, threshold: [0, 0.25, 0.5, 1.0], rootMargin: "10% 20px" }); test(function() { assert_equals(observer.root, rootDiv) }, "set observer.root"); test(function() { assert_array_equals(observer.thresholds, [0, 0.25, 0.5, 1.0]) }, "set observer.thresholds"); test(function() { assert_equals(observer.rootMargin, "10% 20px 10% 20px") }, "set observer.rootMargin"); }, "Observer attribute getters."); </script>