css/css-highlight-api/highlight-text-replace.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Multiple custom highlight pseudo elements.</title>
    <link rel="help" href="https://drafts.csswg.org/css-highlight-api-1/#creating-highlights">
    <link rel="match" href="highlight-text-replace-ref.html">
    <meta name="assert" content="Multiple highlights should be able to be specified.">
    <style>
        ::highlight(example-highlight) {
            background-color: yellow;
            color:green;
        }
    </style>
</head>
<body>
    <span id="text1">One two three</span>

    <script>
        let textElement = document.getElementById('text1');
        let highlight1 = new Highlight(new StaticRange({startContainer: textElement.childNodes[0], startOffset: 1, endContainer: textElement.childNodes[0], endOffset: 2}));

        let highlight2 = new Highlight(new StaticRange({startContainer: textElement.childNodes[0], startOffset: 3, endContainer: textElement.childNodes[0], endOffset: 4}));
        highlight2.add(new StaticRange({startContainer: textElement.childNodes[0], startOffset: 5, endContainer: textElement.childNodes[0], endOffset: 6}));

        CSS.highlights.set("example-highlight", highlight1);
        CSS.highlights.set("example-highlight", highlight2);
    </script>
</body>
</html>