<!doctype html> <title>CSS Shadow Parts - Exporting multiple shadow parts</title> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez"> <link rel="author" href="https://mozilla.org" title="Mozilla"> <link rel="help" href="https://drafts.csswg.org/css-shadow-parts/"> <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1618509"> <style> ::part(inner-part) { color: red; background: blue; width: 100px; height: 100px; } ::part(inner-part-alias) { color: green; } .change-1::part(inner-part) { background: green; } .change-2::part(inner-part-alias) { color: blue; } </style> <div id="outer"></div> <script> test(function() { let outer = document.getElementById("outer"); outer.attachShadow({ mode: "open" }).innerHTML = ` <div exportparts="inner-part, inner-part: inner-part-alias"></div> `; let inner = outer.shadowRoot.querySelector("div"); inner.attachShadow({ mode: "open" }).innerHTML = ` <div part="inner-part"></div> `; let innerPart = inner.shadowRoot.querySelector("div"); assert_equals( getComputedStyle(innerPart).color, "rgb(0, 128, 0)", "color should be green from ::part(inner-part-alias) rule" ); assert_equals( getComputedStyle(innerPart).backgroundColor, "rgb(0, 0, 255)", "background should be blue from ::part(inner-part) rule" ); outer.classList.add("change-1"); assert_equals( getComputedStyle(innerPart).color, "rgb(0, 128, 0)", "color should be green from ::part(inner-part-alias) rule" ); assert_equals( getComputedStyle(innerPart).backgroundColor, "rgb(0, 128, 0)", "background should be green from .change-1::part(inner-part) rule" ); outer.classList.add("change-2"); assert_equals( getComputedStyle(innerPart).color, "rgb(0, 0, 255)", "color should be blue from .change-2::part(inner-part-alias) rule" ); assert_equals( getComputedStyle(innerPart).backgroundColor, "rgb(0, 128, 0)", "background should be green from .change-1::part(inner-part) rule" ); }, "Forwarding part under multiple names should work"); </script>