JSFiddle - React, Tailwind, and code Playground

HTML

<font> Maximum Number of characters for this text box is 255.<br>
<textarea onKeyPress="countCharsLeft(this)" onKeyUp="countCharsLeft(this)" name="Description" rows=7 wrap="physical" cols=40 maxlength="255">
</textarea>
<br><br>
You have <B><SPAN id="myCounter">255</SPAN></B> characters remaining for your description...    </font>

<script>
function countCharsLeft(element){
  var curCharCount = element.value.length;
  var maxLength = element.getAttribute("maxlength");
  document.getElementById("myCounter").innerHTML = maxLength-curCharCount;
}

</script>