I have this table:

<table>
    <thead>
        <tr>
            <th>ONE</th>
            <th>TWO</th>
            <th>THREE</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
        </tr>
        <tr class="myDataRow" data-mydata="my data info">
            <td>4</td>
            <td>4</td>
            <td>5</td>
        </tr>
        <tr>
            <td>6</td>
            <td>7</td>
            <td>8</td>
        </tr>
    </tbody>
</table>

With this style:

.myDataRow > td:last-child::before {
    content: attr(data-mydata);
}

However, “my data info” does not show up before the TD.

If I do this, however:

.myDataRow > td:last-child::before {
    content: "TEST";
}

The word “TEST” shows up fine.

Why is this not working with the data attribute value?