实例 3-37 将HTML 替换成文本
本实例演示了如何通过preg_replace 函数将HTML 替换成文本，如代码3-37 所示。
【代码 3-37】 preg_replace_2.php
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> preg_replace_2.php </title>
<meta charset="UTF-8">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
</head> <body>
<?php
$document=<<<HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> New Document </title>
<meta charset="UTF-8">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
</head> <body>
<script type="text/javascript">
//
//
//
alert("Hi world");
</script>
Hello World!<br>
</body>
</html>
HTML;
// $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[^>]*?>.*?</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);
echo $text;
?>
<hr><hr> </body>
</html><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> preg_replace_2.php </title>
<meta charset="UTF-8">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
</head> <body>
New Document
Hello World!
<hr><hr> </body>
</html>
