JSFiddle - React, Tailwind, and code Playground

HTML

<table id="table">
    <tr>
        <td>1 Ferrari F138</td>
        <td>1 000€</td>
        <td>1 200€</td>
        <td>Model monopostu stajne Scuderia Ferrari pre sezónu 2013</td>
        <td>1</td>
        <td>F138</td>
        <td>Klik pre detaily</td>
    </tr>
    <tr>
        <td>2 Ferrari F138</td>
        <td>1 000€</td>
        <td>1 200€</td>
        <td>Model monopostu stajne Scuderia Ferrari pre sezónu 2013</td>
        <td>1</td>
        <td>F138</td>
        <td>Klik pre detaily</td>
    </tr>
    <tr>
        <td>3 Ferrari F138</td>
        <td>1 000€</td>
        <td>1 200€</td>
        <td>Model monopostu stajne Scuderia Ferrari pre sezónu 2013</td>
        <td>1</td>
        <td>F138</td>
        <td>Klik pre detaily</td>
    </tr>
</table>

    <input type="button" id="tst" value="OK" onclick="fnselect()" />

CSS

td {border: 1px #DDD solid; padding: 5px; cursor: pointer;}

.selected {
    background-color: brown;
    color: #FFF;
}

JavaScript

function highlight(e) {
    if (selected[0]) selected[0].className = '';
    e.target.parentNode.className = 'selected';
}

var table = document.getElementById('table'),
    selected = table.getElementsByClassName('selected');
table.onclick = highlight;

function fnselect(){
    
    alert($("tr.selected td:first" ).html());
}