<!DOCTYPE html>
<title>@container-dependent elements respond to size changes of an @container-dependent iframe</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional-5/#size-container">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/cq-testcommon.js"></script>
<style>
#container {
container-type: size;
width: 200px;
height: 200px;
}
iframe {
width: 200px;
height: 40px;
}
@container (width > 300px) {
iframe { width: 400px; }
}
</style>
<div id=container>
<iframe id=iframe srcdoc="
<style>
div#container {
container-type: size;
height: 20px;
}
div#child { color: red; }
@container (width > 300px) {
div#child { color: green; }
}
</style>
<div id=container>
<div id=child>Test</div>
</div>
"></iframe>
</div>
<script>
setup(() => assert_implements_container_queries());
function waitForLoad(w) {
return new Promise(resolve => w.addEventListener('load', resolve));
}
promise_test(async () => {
await waitForLoad(window);
let inner_div = iframe.contentDocument.querySelector('div#child');
assert_equals(getComputedStyle(inner_div).color, 'rgb(255, 0, 0)');
// Changing the size of the outer container changes the size of the iframe,
// which in turn should change the size of the inner container (inside that
// iframe).
container.style.width = '400px';
container.style.setProperty('--x', 'x'); // crbug.com/1312940
assert_equals(getComputedStyle(inner_div).color, 'rgb(0, 128, 0)');
});
</script>