JSFiddle - React, Tailwind, and code Playground
by Vitaliy
HTML
<table>
<tr>
<td>How did you hear about us:</td>
<td>
<input type="checkbox" name="advertising" value="tv"/> Advertising on TV <br>
<input type="checkbox" name="advertising" value="radio"/> Advertising on Radio <br>
<input type="checkbox" name="advertising" value="internet"/> Advertising Internet <br>
<input type="checkbox" name="advertising" value="subway"/> Advertising in Subway <br>
<input type="checkbox" name="advertising" value="other"/> Other <br>
</td>
</tr>
<tr>
<td>Other:</td>
<td>
<textarea disabled name="other"></textarea></p>
</td>
</tr>
</table>
JavaScript
document.querySelector('input[value="other"]').onchange = function(){
var textarea = document.querySelector('textarea[name="other"]');
textarea.disabled ? textarea.disabled = false : textarea.disabled = true;
}