JSFiddle - React, Tailwind, and code Playground

HTML

<p>This does not work properly in Firefox 5.  It works in Safari, Chrome, IE and Opera.</p>
<p>All the cells in the 8th column should be bold with blue background.  Both selectors in the javascript are essentially identical, but the first one does not work in Firefox 5.  Instead, various other cells are bolded.</p>

<table id="dataTable">
    <thead>
        <tr>
            <th>1</th><th>2</th><th>3</th><th>4</th><th>5</th><th>6</th><th>7</th><th>8</th><th>9</th><th>10</th><th>11</th><th>12</th><th>13</th><th>14</th><th>15</th>
        <th>Total</th></tr>
    </thead>
    <tbody>
        <tr>
            <td>Category</td><td class="valueCell">63</td><td class="valueCell">1,322</td><td class="valueCell">2,538</td><td class="valueCell">2,187</td><td>-</td><td>-</td><td class="valueCell">12,146</td><td class="valueCell">1,014</td><td class="valueCell">4,452</td><td class="valueCell">3,670</td><td class="valueCell">361</td><td class="valueCell">507</td><td>-</td><td class="valueCell">2,200</td>
        <td class="valueCell">30,460</td></tr><tr>
            <td>Category</td><td class="valueCell">88</td><td class="valueCell">1,036</td><td class="valueCell">1,365</td><td class="valueCell">434</td><td class="valueCell">1</td><td>-</td><td class="valueCell">3,021</td><td class="valueCell">723</td><td class="valueCell">1,114</td><td class="valueCell">1,306</td><td class="valueCell">272</td><td class="valueCell">64</td><td>-</td><td class="valueCell">924</td>
        <td class="valueCell">10,348</td></tr><tr>
            <td>Category</td><td>-</td><td class="valueCell">74</td><td class="valueCell">111</td><td class="valueCell">138</td><td>-</td><td>-</td><td class="valueCell">1,325</td><td class="valueCell">190</td><td class="valueCell">186</td><td class="valueCell">100</td><td class="valueCell">14</td><td class="valueCell">2</td><td>-</td><td class="valueCell">135</td>
        <td class="valueCell">2,275</td></tr><tr>
            <td>Category</td><td>-</td><td...

CSS

#dataTable td {
    padding: 4px;
    border: 1px solid #ccc;
}

JavaScript

//all cells with a value (not a hypen) in column "8" should have bold text
$("#dataTable tbody td:nth-child(8).valueCell").css("font-weight", "bold");
//instead, various other cells are given bold text
$("#dataTable tbody td:nth-child(8)").filter(".valueCell").css("backgroundColor", "blue");