protected function renderHeader()
	{
		echo "<ul class=\"tabs\">\n";
		foreach($this->tabs as $id=>$tab)
		{
			$title=isset($tab['title'])?$tab['title']:'undefined';
			$active=$id===$this->activeTab?' class="active"' : '';
			$url=isset($tab['url'])?$tab['url']:"#{$id}";
			echo "<li><a href=\"{$url}\"{$active}>{$title}</a></li>\n";
		}
		echo "</ul>\n";
	}