过滤带有html标签的内容

详细内容可以参考
周小蛇的秘密花园 ---- PHP手写方法之 过滤HTML字符
http://zhousir.net/php-html-filtering-method-handwritten-characters.html

function html2text($str){
	$str	=	trim($str);
	$str = preg_replace("/||/isU","",$str);
	$alltext = "";
	$start = 1;
	for($i=0;$i31){
		$alltext .= $str[$i];
			}
		}
	}
	$alltext = str_replace("　"," ",$alltext);
	$alltext = preg_replace("/&([^;&]*)(;|&)/","",$alltext);
	$alltext = preg_replace("/[ ]+/s"," ",$alltext);
	$alltext	=	htmlspecialchars($alltext,ENT_QUOTES);
	return $alltext;
}