<button data-show-button="hgahsj">Еще одна кнопка</button>

<div>
  <span></span>
  <span></span>
  <span></span>
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  <span></span>
</div>
<button data-show-button="hgahsj">Показать еще</button>
<div data-show-block="hgahsj" style="display:none;">
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
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  <span></span>
  <span></span>
  <span></span>
  <span></span>
</div>
span {
  display: block;
  background-color: #666;
  width: 100px;
  height: 40px;
  margin: 5px;
}
$.each($('[data-show-block]'), function() {
  if ($(this).children().length <= 15) {
    var id = $(this).attr('data-show-block');
    $('[data-show-button="'+ id +'"]').hide();
  }
});

$('[data-show-button]').on('click touch', function(event) {
  event.preventDefault();
  var id = $(this).attr('data-show-button');
  $('[data-show-block="'+ id +'"]').show();
  $('[data-show-button="'+ id +'"]').hide();
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js