字符串（含中文）反向输出

function reverse_c( $str ) {   
      $nstr = '';    
       for( $i = strlen($str); $i >= 0; $i--  ){            
              if( ord( substr($str, $i, 1)) > 0xa0 ) {
                 $i -= 1;                         
                 $nstr .= $str[$i] . $str[$i+1];
            } else {           
                 $nstr .= $str[$i]; 
         }                  
    }                              
    return $nstr;     
}
$str='This is a 测试！';
print_r(reverse_c($str));