JSFiddle - React, Tailwind, and code Playground

HTML

<pre id="data">1,2,3,4
5,6,7,8
9,0,1,2
3,4,5,6</pre>
<div id="table"></div>

JavaScript

var table = '';
    var rows = new Array();

    rows = document.getElementById('data').innerHTML.split('\n');
    table += '<table>'

    for(var i = 0; i < rows.length; i++) {
        var columns = rows[i].split(',');
        table += '<tr>';

        for(var j = 0; j < columns.length; j++) {
            table += '<td>' + columns[j] + '</td>';
        }

        table += '</tr>';
    }
        
    table += '</table>';
    document.getElementById('table').innerHTML = table;