Source code
Revision control
Copy as Markdown
Other Tools
Test Info:
- This WPT test may be referenced by the following Test IDs:
- /css/mediaqueries/mq-dynamic-empty-children.html - WPT Dashboard Interop Dashboard
<!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">
<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>