去除重复嵌套的html标签函数

 1 function strip_multi_tags($str, $tag = 'div'){
 2     preg_match_all('/<'.$tag.'>|<\/'.$tag.'>/is', $str, $matched);
 3     $divs   = $matched[0];
 4     $pairs  = array();
 5     foreach($divs as $k => $v){
 6         if($v == '<'.$tag.'>'){
 7             $begin_keys[] = $k;
 8         } else {
 9             $bk = array_pop($begin_keys);
10             if(!is_null($bk)){
11                 $pairs[$bk] = $k;
12             }
13         }
14     }
15 
16     $datas  = preg_split('/<'.$tag.'>|<\/'.$tag.'>/is', $str);
17     $result = '';
18     foreach($datas as $k => $v){
19         if(isset($datas[$k+1]) && strlen(trim($datas[$k+1])) == 0 
20             && isset($pairs[$k]) && isset($pairs[$k+1]) 
21             && ($k+1 + $pairs[$k+1]) == ($k + $pairs[$k]))
22         {
23             unset($divs[$k], $divs[$pairs[$k]]);
24         }
25         $result .= (strlen(trim($v))? $v: ''). (isset($divs[$k])? $divs[$k]: '');
26     }
27     return $result;
28 }