css/css-fonts/font-palette-modify.html

<!DOCTYPE html>
<html class="reftest-wait">
<head>
<meta charset="utf-8">
<title>Tests that dynamically modifying font-palette causes the necessary rendering update</title>
<link rel="help" href="https://drafts.csswg.org/css-fonts/#font-palette-prop">
<link rel="author" title="Myles C. Maxfield" href="mailto:mmaxfield@apple.com">
<link rel="mismatch" href="font-palette-modify-notref.html">
<style>
@font-face {
    font-family: "COLR-test-font";
    src: url("resources/COLR-palettes-test-font.ttf") format("truetype");
}

@font-palette-values --MyPalette {
    font-family: "COLR-test-font";
    base-palette: 1;
}

@font-palette-values --MyPalette2 {
    font-family: "COLR-test-font";
    base-palette: 0;
    /* Glyph 'A' uses palette indices 3 and 7. */
    override-colors: 3 #00FF00;
}
</style>
</head>
<body>
<div id="target" style="font: 48px 'COLR-test-font'; font-palette: --MyPalette;">A</div>
<script>
let count = 0;
function tick() {
    if (count > 3) {
        document.getElementById("target").style.setProperty("font-palette", "--MyPalette2");
        document.documentElement.classList.remove("reftest-wait");
    } else {
        ++count;
        requestAnimationFrame(tick);
    }
}
[...document.fonts][0].load().then(tick);
</script>
</body>
</html>