How can fix the remainning characters counter in js

I will create a javascript remaining character counter for an HTML textarea. But my code is not working. How can I fix this.

$(document).ready(function(){

  var length = 0;
  var maximumCharacters = 160;

  $('#description').keyup(function(){
    length = this.value.length;

    if(length > maximumCharacters){

      return false;

    } else if (length > 0){

      $("#remaining-characters").html("Remaining characters: " + (maximumCharacters-length));

    } else {

      $("#remaining-characters").html("Remaining characters: " + maximumCharacters);

    }
  })
})
<div class="row mb-3">
        <label for="description" class="col-sm-2 col-form-label label">Description</label>
        <div class="col-sm-10">
          <textarea class="form-control form textarea" id="description" name="description" maxlength="160"></textarea><span id="remaining-characters"></span>
        </div>
      </div>