How to remove all comments from web page files in php

$search = array ("&#39;<script[^>]*?>.*?</script>&#39;si", // 去掉 javascript
 "&#39;<style[^>]*?>.*?</style>&#39;si",  // 去掉 css
 "&#39;<[/!]*?[^<>]*?>&#39;si",      // 去掉 HTML 标记
 "&#39;<!--[/!]*?[^<>]*?>&#39;si",      // 去掉 注释 标记
 "&#39;([rn])[s]+&#39;",  // 去掉空白字符
 "&#39;&(quot|#34);&#39;i",  // 替换 HTML 实体

 "&#39;&(amp|#38);&#39;i",
 "&#39;&(lt|#60);&#39;i",
 "&#39;&(gt|#62);&#39;i",
 "&#39;&(nbsp|#160);&#39;i",
 "&#39;&(iexcl|#161);&#39;i",
 "&#39;&(cent|#162);&#39;i",
 "&#39;&(pound|#163);&#39;i",
 "&#39;&(copy|#169);&#39;i",
 "&#39;(d+);&#39;e");   // 作为 PHP 代码运行
 
$replace = array ("",
 "",
 "",
 "",
 "\1",
 "\"",
 "&",
 "<", 
 ">",
 " ",
 chr(161),
 chr(162),
 chr(163),
 chr(169),
 "chr(\1)");
//$document为需要处理字符串，如果来源为文件可以$document = file_get_contents($filename);
$out = preg_replace($search, $replace, $document);