核心代码：
PHP;">
PHP
// $document 应包含一个 HTML 文档。
// 本例将去掉 HTML 标记，javascript 代码
// 和空白字符。还会将一些通用的
// HTML 实体转换成相应的文本。
$search = array ("'<script[^>]?>.?'si",// 去掉 javascript
"'<[\/!]?[^<>]?>'si",// 去掉 HTML 标记
"'([\r\n])[\s]+'",// 去掉空白字符
"'&(quot|#34);'i",// 替换 HTML 实体
"'&(amp|#38);'i","'&(lt|#60);'i","'&(gt|#62);'i","'&(nbsp|#160);'i","'&(iexcl|#161);'i","'&(cent|#162);'i","'&(pound|#163);'i","'&(copy|#169);'i","'&#(\d+);'e"); // 作为 PHP 代码运行
$replace = array ("","","\1","\"","&","<",">"," ",chr(161),chr(162),chr(163),chr(169),"chr(\1)");
$text = preg_replace ($search,$replace,$document);
?>