去除重复嵌套的html标签函数

去除重复嵌套的html标签

 function strip_multi_tags($str, $tag = 'div'){
     preg_match_all('/<'.$tag.'>|<\/'.$tag.'>/is', $str, $matched);
     $divs   = $matched[0];
     $pairs  = array();
     foreach($divs as $k => $v){
         if($v == '<'.$tag.'>'){
             $begin_keys[] = $k;
         } else {
             $bk = array_pop($begin_keys);
             if(!is_null($bk)){
                 $pairs[$bk] = $k;
             }
         }
     }

     $datas  = preg_split('/<'.$tag.'>|<\/'.$tag.'>/is', $str);
     $result = '';
     foreach($datas as $k => $v){
         if(isset($datas[$k+1]) && strlen(trim($datas[$k+1])) == 0
             && isset($pairs[$k]) && isset($pairs[$k+1])
             && ($k+1 + $pairs[$k+1]) == ($k + $pairs[$k]))
         {
             unset($divs[$k], $divs[$pairs[$k]]);
         }
         $result .= (strlen(trim($v))? $v: ''). (isset($divs[$k])? $divs[$k]: '');
     }
     return $result;
 }