具体方法如下：

HtmlAttributeFilter.class.php类文件如下：

<?php

/** HTML Attribute Filter

* Date: 2013-09-22

* Author: fdipzone

* ver: 1.0

*

* Func:

* public strip 过滤属性

* public setAllow 设置允许的属性

* public setException 设置特例

* public setIgnore 设置忽略的标记

* private findElements 搜寻需要处理的元素

* private findAttributes 搜寻属性

* private removeAttributes 移除属性

* private isException 判断是否特例

* private createAttributes 创建属性

* private protect 特殊字符转义

*/

class HtmlAttributeFilter{ // class start

private $_str = ''; // 源字符串

private $_allow = array(); // 允许保留的属性 例如:array('id','class','title')

private $_exception = array(); // 特例 例如:array('a'=>array('href','class'),'span'=>array('class'))

private $_ignore = array(); // 忽略过滤的标记 例如:array('span','img')

/** 处理HTML,过滤不保留的属性

* @param String $str 源字符串

* @return String

*/

public function strip($str){

$this->_str = $str;

if(is_string($this->_str) && strlen($this->_str)>0){ // 判断字符串

$this->_str = strtolower($this->_str); // 转成小写

$res = $this->findElements();

if(is_string($res)){

return $res;

}

$nodes = $this->findAttributes($res);

$this->removeAttributes($nodes);

}

return $this->_str;

}

/** 设置允许的属性

* @param Array $param

*/

public function setAllow($param=array()){

$this->_allow = $param;

}

/** 设置特例

* @param Array $param

*/

public function setException($param=array()){

$this->_exception = $param;

}

/** 设置忽略的标记

* @param Array $param

*/

public function setIgnore($param=array()){

$this->_ignore = $param;

}

/** 搜寻需要处理的元素 */

private function findElements(){

$nodes = array();

preg_match_all("/<([^ !/>n]+)([^>]*)>/i", $this->_str, $elements);

foreach($elements[1] as $el_key => $element){

if($elements[2][$el_key]){

$literal = $elements[0][$el_key];

$element_name = $elements[1][$el_key];

$attributes = $elements[2][$el_key];

if(is_array($this->_ignore) && !in_array($element_name, $this->_ignore)){

$nodes[] = array('literal'=>$literal, 'name'=>$element_name, 'attributes'=>$attributes);

}

}

}

if(!$nodes[0]){

return $this->_str;

}else{

return $nodes;

}

}

/** 搜寻属性

* @param Array $nodes 需要处理的元素

*/

private function findAttributes($nodes){

foreach($nodes as &$node){

preg_match_all("/([^ =]+)s*=s*["|']{0,1}([^"']*)["|']{0,1}/i", $node['attributes'], $attributes);

if($attributes[1]){

foreach($attributes[1] as $att_key=>$att){

$literal = $attributes[0][$att_key];

$attribute_name = $attributes[1][$att_key];

$value = $attributes[2][$att_key];

$atts[] = array('literal'=>$literal, 'name'=>$attribute_name, 'value'=>$value);

}

}else{

$node['attributes'] = null;

}

$node['attributes'] = $atts;

unset($atts);

}

return $nodes;

}

/** 移除属性

* @param Array $nodes 需要处理的元素

*/

private function removeAttributes($nodes){

foreach($nodes as $node){

$node_name = $node['name'];

$new_attributes = '';

if(is_array($node['attributes'])){

foreach($node['attributes'] as $attribute){

if((is_array($this->_allow) && in_array($attribute['name'], $this->_allow)) || $this->isException($node_name, $attribute['name'], $this->_exception)){

$new_attributes = $this->createAttributes($new_attributes, $attribute['name'], $attribute['value']);

}

}

}

$replacement = ($new_attributes) ? "<$node_name $new_attributes>" : "<$node_name>";

$this->_str = preg_replace('/'.$this->protect($node['literal']).'/', $replacement, $this->_str);

}

}

/** 判断是否特例

* @param String $element_name 元素名

* @param String $attribute_name 属性名

* @param Array $exceptions 允许的特例

* @return boolean

*/

private function isException($element_name, $attribute_name, $exceptions){

if(array_key_exists($element_name, $this->_exception)){

if(in_array($attribute_name, $this->_exception[$element_name])){

return true;

}

}

return false;

}

/** 创建属性

* @param String $new_attributes

* @param String $name

* @param String $value

* @return String

*/

private function createAttributes($new_attributes, $name, $value){

if($new_attributes){

$new_attributes .= " ";

}

$new_attributes .= "$name="$value"";

return $new_attributes;

}

/** 特殊字符转义

* @param String $str 源字符串

* @return String

*/

private function protect($str){

$conversions = array(

"^" => "^",

"[" => "[",

"." => ".",

"$" => "$",

"{" => "{",

"*" => "*",

"(" => "(",

"\" => "\\",

"/" => "/",

"+" => "+",

")" => ")",

"|" => "|",

"?" => "?",

"<" => "<",

">" => ">"

);

return strtr($str, $conversions);

}

} // class end

?>

demo示例代码如下：

<?php

require('HtmlAttributeFilter.class.php');

$str = '<div class="bd clearfix" id="index_hilite_ul"><ul class="list"><li><img src="http://su.bdimg.com/static/skin/img/logo_white.png" width="118" height="148"><div class="cover"><a class="text" href="http://www.jb51.net"><strong>yuna</strong><p>love</p></a><strong class="t g">want to know</strong><a href="/login.html" class="ppBtn"><strong class="text">YES</strong></a></div></li></ul></div>';

$obj = new HtmlAttributeFilter();

// 允许id属性

$obj->setAllow(array('id'));

$obj->setException(array(

'a' => array('href'), // a 标签允许有 href属性特例

'ul' => array('class') // ul 标签允许有 class属性特例

));

// img 标签忽略,不过滤任何属性

$obj->setIgnore(array('img'));

echo 'source str:<br>';

echo htmlspecialchars($str).'<br><br>';

echo 'filter str:<br>';

echo htmlspecialchars($obj->strip($str));

?>

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