php clean html 可以设置过滤及保留属性
类：
functionreg_escape($str)
{
$conversions=array("^"=>"\^","["=>"\[","."=>"\.","$"=>"\$","{"=>"\{","*"=>"\*","("=>"\(","\\" => "\\\\", "/" => "\/", "+" => "\+", ")" => "\)", "|" => "\|", "?" => "\?", "<" => "\<", ">" => "\>" );
returnstrtr($str,$conversions);
}
/**
* Strip attribute Class
* Remove attributes from XML elements
* @author David (semlabs.co.uk)
* @version 0.2.1
*/
classcleanHtml{
public$str='';
public$allow=array();
public$exceptions=array();
public$ignore=array();
publicfunctionstrip($str)
{
$this->str =$str;
if(is_string($str) &&strlen($str) > 0 )
{
$res=$this->findElements();
if(is_string($res) )
return$res;
$nodes=$this->findAttributes($res);
$this->removeAttributes($nodes);
}
return$this->str;
}
privatefunctionfindElements()
{
# Create anarrayof elements with attributes
$nodes=array();
preg_match_all("/<([^ !\/\>\n]+)([^>]*)>/i",$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);
}
}
# Return the XMLifthere were no attributes to remove
if( !$nodes[0] )
return$this->str;
else
return$nodes;
}
privatefunctionfindAttributes($nodes)
{
# Extract attributes
foreach($nodesas&$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;
}
privatefunctionremoveAttributes($nodes)
{
# Remove unwanted attributes
foreach($nodesas$node)
{
# Checkifnode has any attributes to be kept
$node_name=$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->exceptions ) )
$new_attributes=$this->createAttributes($new_attributes,$attribute['name'],$attribute['value'] );
}
}
$replacement= ($new_attributes) ?"<$node_name $new_attributes>":"<$node_name>";
$this->str = preg_replace('/'. reg_escape($node['literal'] ) .'/',$replacement,$this->str );
}
}
privatefunctionisException($element_name,$attribute_name,$exceptions)
{
if(array_key_exists($element_name,$this->exceptions) )
{
if( in_array($attribute_name,$this->exceptions[$element_name] ) )
returntrue;
}
returnfalse;
}
privatefunctioncreateAttributes($new_attributes,$name,$value)
{
if($new_attributes)
$new_attributes.=" ";
$new_attributes.="$name=\"$value\"";
return$new_attributes;
}
}
实例：
$str ='Here is some sample html that is getting broken ';
$sa =newcleanHtml;
$sa->allow = array('id');
$sa->exceptions = array(
'img'=> array('src','alt'),
'a'=> array('href','title'),
'iframe'=>array('src','frameborder'),
);
echo $str = $sa->strip( $str );
来源：semlabs.co.uk
原文：http://justcoding.iteye.com/blog/1473623
其他：http://blog.csdn.net/china_skag/article/details/7551072
