HTML Table

HTML

<table id="codexpl">
    <tr>
        <th>#</th>
        <th>Columna</th>
        <th>Relative</th>
        <th>Isso</th>
    </tr>
    <tr>
        <td>Coluna 1</td>
        <td><input type="text" readonly="readonly" /></td>
        <td><input type="text" readonly="readonly" /></td>
        <td><button class="btn_alt">Alterar</button></td>
    </tr>

</table>

CSS

#codexpl th, #codexpl td{
    padding:0.8em;
    border: 1px solid;
}
#codexpl th{
    background-color:#6699FF;
    font-weight:bold;
}

JavaScript

$('tr td .btn_alt').on('click', function () {
    $(this).closest('tr').find('input').attr('readonly', false);
});