JSFiddle - React, Tailwind, and code Playground

by perodinamit

HTML

<table id="test">
    
    <tr><td class="category_1">Ivo</td><td>Test</td></tr>
    <tr><td class="category_1">Pero</td><td>Test1</td></tr>
    <tr><td class="category_1">Milena</td><td>Test</td></tr>
    <tr><td class="category_1">Ivo</td><td>Test</td></tr>
    <tr><td class="category_1">Marko</td><td>Test1</td></tr>
    <tr><td class="category_1">Pero</td><td>Test</td></tr>
     
</table>

JavaScript

var duplicate = [];
$('#test .category_1').each(function() {
    var text = $(this).text();
    if ($.inArray(text, duplicate) === -1) {
        duplicate.push(text);
    } else {
        $(this).css("background-color", "#FFAA00");
    }
});