JSFiddle - React, Tailwind, and code Playground

HTML

<p><strong>Adapted from <a href="http://stackoverflow.com/questions/2006468/copy-paste-from-excel-to-a-web-page">http://stackoverflow.com/questions/2006468/copy-paste-from-excel-to-a-web-page</a></strong></p>

<p>Paste excel data here:</p>
<textarea id="pastein" name="excel_data" style="width:250px;height:150px;"></textarea><br>
<!-- <input type="button" onclick="javascript:generateTable()" value="Genereate Table"/> -->
<br><br>
<p>Table data will appear below</p>
<hr>
<div id="excel_table"></div>

CSS

table {
  border-collapse: collapse;
  border: 1px solid #000000;
}

table td {
  border: 1px solid #000000;
}

JavaScript

function removeExtraTabs(string) {
    return string.replace(new RegExp("\t\t", 'g'), "\t");
}

function generateTable() {
  var data = removeExtraTabs($('#pastein').val());
  var rows = data.split("\n");
  var table = $('<table />');

  for (var y in rows) {
    rows[y] = removeExtraTabs(rows[y]);
    var cells = rows[y].split("\t");
    var row = $('<tr />');
    for (var x in cells) {
      row.append('<td>' + cells[x] + '</td>');
    }
    table.append(row);
  }

  // Insert into DOM
  $('#excel_table').html(table);
}

$(document).ready(function() {
  $('#pastein').on('paste', function(event) {
    $('#pastein').on('input', function() {
      generateTable();
      $('#pastein').off('input');
    })
  })
})