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console 命令行工具 X clear

                    
>
console
$(document).ready(function() {
  var maxLength = $('#comments').attr('maxLength');
  $('textarea').keyup(function() {
    var inputLength = $(this).val().length;
    var remainLength = maxLength-inputLength;
    $('#charCount').text(remainLength);
  });
});
<div class='textArea__wrapper'>
    <label class='fieldLabel ' for='comments'>Anything else you&#39;d like us to know?</label></br>
    <textarea id='comments' name="comments" rows='5' placeholder='Maximum 500 characters'
      class='comments'
      maxLength='500'></textarea>
    <div aria-live='polite' aria-atomic='true' class="counter__Wrapper"><span id="charCount">500</span>&nbsp;<span class='invisibleTxt'>characters remaining</span></div>
</div>
.textArea__wrapper{
    position: relative;
    display: inline-block;
  }
  .comments {
    width: 300px;
    height: 200px;
    resize: none;
  }
  .counter__Wrapper{
    position: absolute;
    right: 0;
    bottom: 8px;
  }
  .invisibleTxt{
    position: absolute;
    left: -999em;
  }

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