$( document ).ready(function() {
  if ($('article').height() > 560){
    $('article').readmore({
      speed: 500,
      collapsedHeight: 580,
      lessLink: '<a href="#"> <span class="glyphicon glyphicon-minus-sign icona_readmore" aria-hidden="true"></span> </a>',
      moreLink: '<a href="#"> <span class="glyphicon glyphicon-plus-sign icona_readmore" aria-hidden="true"></span> </a>'
    });
  }
});