JSFiddle - React, Tailwind, and code Playground

HTML

<table>
  <tr>
    <td>Test code 1</td>
    <td>
      <input type='text' id='input1' class="selection" />
    </td>
  </tr>
  <tr>
    <td>Test code 2</td>
    <td>
      <input type='text' id='input2' class="selection" />
    </td>
  </tr>
</table>

JavaScript

var els = document.getElementsByClassName('selection');
function getSelection(textComponent) {
  var selectedText;
  if (textComponent.selectionStart !== undefined) { // Standards Compliant Version
    var startPos = textComponent.selectionStart;
    var endPos = textComponent.selectionEnd;
    selectedText = textComponent.value.substring(startPos, endPos);
  } else if (document.selection !== undefined) { // IE Version
    textComponent.focus();
    var sel = document.selection.createRange();
    selectedText = sel.text;
  }
  return selectedText;
}

for (var i = 0; i < els.length; i++) {
  els[i].addEventListener('mouseup', function() {
    this.value = getSelection(this);
  })
}