function equalHeight() {

  var $primary = $('div.primary'); // Save primary area
  var $secondary = $('div.secondary'); // Save secondary area
  
  if ($primary.height() !== $secondary.height()) {
    
    if ($primary.height() > $secondary.height()) {
      
      var $height = $primary.height();
      
      $secondary.height($height);
      
    } else {
      
      var $height = $secondary.height();
      
      $primary.height($height);
      
    } 
  }  
}

$(document).load(setTimeout('equalHeight()', 500));