| <!doctype html> |
| <title>Dynamic evaluation of media queries works fine in presence of empty media rule</title> |
| <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://bugzilla.mozilla.org/show_bug.cgi?id=1669600"> |
| <link rel="help" href="https://drafts.csswg.org/mediaqueries-4/"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <iframe width=500 height=300 frameborder=0></iframe> |
| <script> |
| let iframe = document.querySelector("iframe"); |
| promise_test(async function (t) { |
| await new Promise(resolve => { |
| window.addEventListener("load", resolve); |
| }); |
| let frameLoaded = new Promise(resolve => { |
| iframe.addEventListener("load", resolve); |
| }); |
| iframe.srcdoc = ` |
| <style> |
| :root { background-color: red; } |
| /* This one should never apply */ |
| @media (min-width: 1500px) {} |
| /* This one should change and start matching */ |
| @media (max-width: 400px) { |
| :root { background-color: lime; } |
| } |
| </style> |
| `; |
| await frameLoaded; |
| |
| function getColor() { |
| return iframe.contentWindow.getComputedStyle(iframe.contentDocument.documentElement).backgroundColor; |
| } |
| |
| assert_equals(getColor(), "rgb(255, 0, 0)", "Should start red"); |
| iframe.width = 400; |
| assert_equals(getColor(), "rgb(0, 255, 0)", "Should turn green"); |
| }); |
| </script> |
