| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>MutationObserver: callback arguments</title> |
| <link rel="help" href="https://dom.spec.whatwg.org/#notify-mutation-observers"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <div id="mo-target"></div> |
| <div id="log"></div> |
| <script> |
| "use strict"; |
| |
| async_test(t => { |
| const moTarget = document.querySelector("#mo-target"); |
| const mo = new MutationObserver(function(records, observer) { |
| t.step(() => { |
| assert_equals(this, mo); |
| assert_equals(arguments.length, 2); |
| assert_true(Array.isArray(records)); |
| assert_equals(records.length, 1); |
| assert_true(records[0] instanceof MutationRecord); |
| assert_equals(observer, mo); |
| |
| mo.disconnect(); |
| t.done(); |
| }); |
| }); |
| |
| mo.observe(moTarget, {attributes: true}); |
| moTarget.className = "trigger-mutation"; |
| }, "Callback is invoked with |this| value of MutationObserver and two arguments"); |
| </script> |
