public function getNodeAttribute($xPath,$atrName){
        $res = $this->content->xpath($xPath);
        if ($res !== null){
            foreach ($res as $set){
                return (string)$set[$atrName];

            }
        }

        return NULL;
    }
public function getNodeAttribute($xPath,$atrName){
        $res = $this->content->xpath($xPath);
        if ($res !== null){
            foreach ($res as $set){
                return (string)$set[$atrName];

            }
        }

        return NULL;
    }
public function getNodeAttribute ( $ xPath , $ atrName ) { $ res = $ this -> content -> xpath ( $ xPath ) ; if ( $ res !== null ) { foreach ( $ res as $ set ) { return ( string ) $ set [ $ atrName ] ; } } return NULL ; }
reads an spcific attribute from node
@param type $xPath
@param type $atrName
@return string
reads an spcific attribute from node