<!DOCTYPE html>
<meta charset="utf-8">
<title>-webkit-user-modify should be unsupported in CSS.supports</title>
<link rel="help" href="https://developer.mozilla.org/en-US/docs/Web/CSS/user-modify">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
@supports (-webkit-user-modify: read-only) {
    #content {
        width: 10px;
        height: 10px;
        background-color: red;
    }
}
</style>
<div id="content"></div>
<script>
    test(function() {
        const content = document.getElementById('content');
        assert_not_equals(getComputedStyle(content).getPropertyValue('background-color'), 'rgb(255, 0, 0)');
    }, '@supports doesn\'t use unsupported -webkit-user-modify property');

    test(function() {
        const supportsWebkitUserModifyProperty = CSS.supports(`(-webkit-user-modify: read-only) or
            (-webkit-user-modify: read-write) or
            (-webkit-user-modify: read-write-plaintext-only) or
            (-webkit-user-modify: write-only)`);
        assert_equals(supportsWebkitUserModifyProperty, false);
    }, 'CSS.supports doesn\'t use unsupported -webkit-user-modify property');
</script>
