function getYoutubeScreen( url, size ) {   if(url === null){ return ""; }    size = (size === null) ? "big" : size;   var vid;   var results;    results = url.match("[\\?&]v=([^&#]*)");    vid = ( results === null ) ? url : results[1];    if(size == "small"){     return "http://img.youtube.com/vi/"+vid+"/2.jpg";   }else {     return "http://img.youtube.com/vi/"+vid+"/0.jpg";   } 
}

	function toggleBlock(id) {
		if (!document.getElementById)
			return;
		var block = document.getElementById(id);
		if (block.className == 'block_hidden') {
			block.className = 'block_visible';
		}else
			block.className = 'block_hidden';
	};