Aidec,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
table {
border-collapse: collapse;
border: 2px solid rgb(200, 200, 200);
letter-spacing: 1px;
font-family: sans-serif;
font-size: 0.8rem;
}
td,
th {
border: 2px solid rgb(200, 200, 200);
}
td.red {
background-color: #FF0000;
}
</style>
</head>
<body>
<table>
<caption>Alien football stars</caption>
<tr>
<th scope="col">Player</th>
<th scope="col">Gloobles</th>
<th scope="col">Za'taak</th>
</tr>
<tr>
<th scope="row">TR-7</th>
<td>7</td>
<td>4,569</td>
</tr>
<tr>
<th scope="row">Khiresh Odo</th>
<td>7</td>
<td>7,223</td>
</tr>
<tr>
<th scope="row">Mia Oolong</th>
<td>9</td>
<td>6,219</td>
</tr>
</table>
<script>
let patern = '7';
document.querySelectorAll('td').forEach(td => {
let txt = td.textContent;
td.classList.toggle('red', txt.includes(patern))
})
</script>
</body>
</html>