方法基本上来自THinkphp中的源码，但是被我修改了一下
复制代码 代码如下:
<?php
/*
*@Description:删除HTML标签，得到纯文本。可以处理嵌套的标签
*
*/
class deleteHtmlTags{

private $filename;

function __construct($filename='C:/AppServ/www/text.txt'){
$this->filename = $filename;
}

/**
* 删除html标签，得到纯文本。可以处理嵌套的标签,局限性在于连标签内的属性值都会删除掉
* @access public
* @param string $string 要处理的html
* @return string
*/
public function deletehtmltags(){
$content = $this->contentGet();
while(strstr($content, '>')){
$currentBegin = strpos($content, '<');
$currentEnd = strpos($content, '>');
$cha = $currentEnd - $currentBegin - 1;
$tmpStringBegin = @substr($content, 0, $currentBegin);
// $tmpStringMiddle = @ substr($content, $currentBegin + 1, $cha);
$tmpStringEnd = @substr($content, $currentEnd + 1, strlen($content));
// $content = $tmpStringBegin.$tmpStringMiddle.$tmpStringEnd;
$content = $tmpStringBegin.$tmpStringEnd;
}
return $content;
}

private function contentGet(){
$fd = fopen($this->filename, 'r');
$content = fread($fd, filesize($this->filename));
fclose($fd);
return $content;
}
}

$deleteHtml = new deleteHtmlTags();
$content = $deleteHtml->deletehtmltags();
echo $content;
?>

修改部分也在上面，只是注释掉了。个人觉得这个方法比用正则这类的方法更好。