check-useragent.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Check useragent</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>

<script>
    const userAgent = navigator.userAgent || navigator.vendor || window['opera']

    let regexp
    if (/android/.test(userAgent.toLowerCase())) {
        regexp = /fban|fbav|instagram|snapchat|nrk|firefox|opera|klar\//
    } else if (!!navigator.platform && /iPad|iPhone|iPod/.test(navigator.platform)) {
        regexp = /fban|fbav|instagram|snapchat|nrk|firefox|opera|chrome|fxios|crios/
    }

    const issue = regexp.test(userAgent.toLowerCase())


    const p = document.createElement('p')
    p.innerHTML = `
        <dl>
            <dt>userAgent:</dt><dd> ${userAgent}</dd>
            <dt>platform:</dt><dd> ${navigator.platform}</dd>
            <dt>issue:</dt><dd> ${issue}</dd>
        </dl>`
    document.body.appendChild(p)
</script>
</body>
</html>