過濾

<?php
// $document 應包含一個 HTML 文檔。
// 本例將去掉 HTML 標記，javascript 代碼
// 和空白字符。還會將一些通用的
// HTML 實體轉換成相應的文本。

$search = array ("'<script[^>]*?>.*?</script>'si",  // 去掉 javascript
                 "'<[\/\!]*?[^<>]*?>'si",           // 去掉 HTML 標記
                 "'([\r\n])[\s]+'",                 // 去掉空白字符
                 "'&(quot|#34);'i",                 // 替換 HTML 實體
                 "'&(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");                    // 作爲 PHP 代碼運行

$replace = array ("",
                  "",
                  "\\1",
                  "\"",
                  "&",
                  "<",
                  ">",
                  " ",
                  chr(161),
                  chr(162),
                  chr(163),
                  chr(169),
                  "chr(\\1)");

$text = preg_replace ($search, $replace, $document);
?>