Source code
Revision control
Copy as Markdown
Other Tools
<!DOCTYPE html>
<title>CSS Custom Functions: Invalidation when @function rules change</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<!-- This stylesheet will be mutated during testing. -->
<style id=mutable_style>
@function --f() {
result: 10px;
}
</style>
<style>
#outer {
width: 42px;
}
#target {
width: --f();
}
</style>
<div id=outer>
<div>
<div id=target>
</div>
</div>
<div>
<script>
// Adds a cleanup step to recreate `original_element` in-place
// (with the original text).
function add_cleanup(t, original_element) {
let original_text = original_element.textContent;
t.add_cleanup(() => {
let new_element = document.createElement('style');
new_element.setAttribute('id', 'mutable_style');
new_element.textContent = original_text;
original_element.parentElement.replaceChild(new_element, original_element);
});
}
test(t => {
add_cleanup(t, mutable_style);
let sheet = mutable_style.sheet;
assert_equals(getComputedStyle(target).width, '10px');
sheet.insertRule('@function --f() { result: 20px; }', 1);
assert_equals(getComputedStyle(target).width, '20px');
}, 'Appending a rule');
test(t => {
add_cleanup(t, mutable_style);
let sheet = mutable_style.sheet;
assert_equals(getComputedStyle(target).width, '10px');
sheet.insertRule('@function --f() { result: 20px; }', 0);
assert_equals(getComputedStyle(target).width, '10px'); // No change.
}, 'Prepending a rule');
test(t => {
add_cleanup(t, mutable_style);
let sheet = mutable_style.sheet;
assert_equals(getComputedStyle(target).width, '10px');
sheet.deleteRule(0);
assert_equals(getComputedStyle(target).width, '42px');
}, 'Deleting a rule');
test(t => {
add_cleanup(t, mutable_style);
let sheet = mutable_style.sheet;
assert_equals(getComputedStyle(target).width, '10px');
sheet.insertRule('@function --f() { result: 20px; }', 0);
assert_equals(getComputedStyle(target).width, '10px');
sheet.deleteRule(1);
assert_equals(getComputedStyle(target).width, '20px');
}, 'Prepending a rule, then deleting last');
</script>