$(document).ready(function(){
  $('#disclaimer').click(function() {
    $('#dialog').dialog('open');
  });
  
  $('#dialog').dialog({
    bgiframe: true,
    autoOpen: false,
    position: ['center','center'],
    height: 345,
    width: 456,
    modal: true,
    resizable: false,
    buttons: {
        'Sluiten': function() {
        $(this).dialog('close');
      }
    }
  });
});