本文实例讲述了php 过滤html标记属性类及其用法。是PHP项目开发中比较常见的实用技巧。分享给大家供大家参考。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("/<([^ !/>
]+)([^>]*)>/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="//www.yinxi.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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希望本文所述对大家的PHP程序设计有所帮助。