1 
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",22             "number" => "0123456789",23     );24     if (empty($chars_range)) {25         $chars_rang = 'alpha-number';26     }27     if(strpos($chars_range, '-')) {28         $char_range_arr = explode('-',$chars_range);29         foreach($char_range_arr as $range){30             if(!array_key_exists($range, $char_arr)){31                 exit("wrong range \"". $range ."\"");32             }33             $chars .= $char_arr[$range];34         }35     }else{36         if(!array_key_exists($chars_range, $char_arr)){37             exit("wrong range \"".$chars_range ."\"");38         }39         $chars = $char_arr[$chars_range];40     }41     while( strlen($str) < $length) {42         $str .= substr($chars, rand(0, strlen($chars) - 1), 1);43     }44     return $str;45 }46 47 ?>