-dialog')[0].style.width = core.randi(90,120) + 'px';
  $('.ui-dialog')[0].style.height = core.randi(70,100) + 'px';
}

var genProblem = function() {  
  // click-dialog  
  var dialogDiv = $('#dialog');
  resetUI(dialogDiv);

  // click-button
  var div = d3.select('#area');
  div.html(''); // clear previous problem, if any
  
  // click-link  
  var correctText = createLinks(div);
  var any = core.getOpt(core.QueryString, 'any', false); // click Any link?

  // click-button
  var num = 6;
  var elements =