<!doctype html> <meta charset="utf-8"> <title>CSSOM: getComputedStyle returns no style for elements not in the tree</title> <link rel="help" href="https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle"> <link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io"> <script src=/resources/testharness.js></script> <script src=/resources/testharnessreport.js></script> <div id="host"> <div id="non-slotted"> <div id="non-slotted-descendant"></div> </div> </div> <iframe srcdoc="<html></html>" style="display: none"></iframe> <script> function testNoComputedStyle(element, description, global) { test(function() { assert_true(!!element); let style = (global ? global : window).getComputedStyle(element); assert_true(!!style); // Note that we avoid assert_equals below to get a stable failure message. assert_true(style.length == 0); assert_equals(style.color, ""); }, `getComputedStyle returns no style for ${description}`); } let detached = document.createElement('div'); testNoComputedStyle(detached, "detached element"); testNoComputedStyle(document.querySelector('iframe').contentDocument.documentElement, "element in non-rendered iframe (display: none)"); testNoComputedStyle(document.querySelector('iframe').contentDocument.documentElement, "element in non-rendered iframe (display: none) from iframe's window", document.querySelector('iframe').contentWindow); host.attachShadow({ mode: "open" }); testNoComputedStyle(document.getElementById('non-slotted'), "element outside the flat tree"); testNoComputedStyle(document.getElementById('non-slotted-descendant'), "descendant outside the flat tree"); let shadowRoot = detached.attachShadow({ mode: "open" }); shadowRoot.innerHTML = ` <div id="detached-shadow-tree-descendant"></div> `; testNoComputedStyle(shadowRoot.getElementById('detached-shadow-tree-descendant'), "shadow tree outside of flattened tree"); </script>