var openSchuifblok = null;

$(function() {
  $('#schuifblokken-holder .schuiftekst').hide();
  $('#schuifblokken-holder .schuifkop').mouseover(function() {
    var myId = $(this).closest('.schuifblok').attr('id');

    if(openSchuifblok != null && openSchuifblok != myId) {
      $('#' + openSchuifblok).find('.schuiftekst').slideUp('fast');
      openSchuifblok = null;
    }
    else if(openSchuifblok == null || openSchuifblok != myId) {
      $(this).next().slideDown('fast');
      openSchuifblok = myId;
    }
  });
});