PHP 代码如下：

//   ValidateABN
//     Checks ABN for validity using the published
//     ABN checksum algorithm.
//
//     Returns: true if the ABN is valid, false otherwise.
//      Source: http://www.clearwater.com.au/code
//      Author: Guy Carpenter
//     License: The author claims no rights to this code.
//              Use it as you wish.function ValidateABN($abn)
{$weights = array(10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19);// strip anything other than digits$abn = preg_replace("/[^\d]/","",$abn);// check length is 11 digitsif (strlen($abn)==11) {// apply ato check method $sum = 0;foreach ($weights as $position=>$weight) {$digit = $abn[$position] - ($position ? 0 : 1);$sum += $weight * $digit;}return ($sum % 89)==0;} return false;
}

JavaScript 代码如下：

function checkABN(str) {if (!str || str.length !== 11) {return false;}var weights = [10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19],checksum = str.split('').map(Number).reduce(function(total, digit, index) {if (!index) {digit--;}return total + (digit * weights[index]);},0);if (!checksum || checksum % 89 !== 0) {return false;}return true;
}

C# 代码如下：

public static bool ValidateABN(string abn)
{bool isValid = false;int[] weight = { 10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 };int weightedSum = 0;//ABN must not contain spaces, comma's or hypensabn = StripNonDigitData(abn);//ABN must be 11 digits long  if (!string.IsNullOrEmpty(abn) & Regex.IsMatch(abn, "^\\d{11}$")){//Rules: 1,2,3  for (int i = 0; i <= weight.Length - 1; i++){weightedSum += (int.Parse(abn[i].ToString()) - ((i == 0 ? 1 : 0))) * weight[i];}//Rules: 4,5  return ((weightedSum % 89) == 0);}return isValid;
}public static string StripNonDigitData(string input)
{StringBuilder output = new StringBuilder("");foreach (char c in input){if (char.IsDigit(c)){output.Append(c);}}return output.ToString();
}

ABNLookup 查询（需要去 https://abr.business.gov.au/Documentation/WebServiceRegistration 注册一个账号，如果成功，会在5天内收到一封邮件，里面有个GUID），PHP 代码：

<?phpnamespace PPost\Library;class ABNLookup extends \SoapClient{private $guid = "xxxxxxxxxxxxxxxxxx";    // guidpublic function __construct(){$params = array('soap_version' => SOAP_1_1,'exceptions' => true,'trace' => 1,'cache_wsdl' => WSDL_CACHE_NONE); parent::__construct('http://abr.business.gov.au/abrxmlsearch/ABRXMLSearch.asmx?WSDL', $params);}public function searchByAbn($abn, $historical = 'N'){$params = new \stdClass();$params->searchString                = $abn;$params->includeHistoricalDetails    = $historical;$params->authenticationGuid            = $this->guid;return $this->ABRSearchByABN($params);}
}

<?phpnamespace PPost\Infrastructure\Helper;class ABNHelper
{public static function ValidateABN($abn){$weights = array(10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19);// strip anything other than digits$abn = preg_replace("/[^\d]/","",$abn);// check length is 11 digitsif (strlen($abn)==11) {// apply ato check method$sum = 0;foreach ($weights as $position=>$weight) {$digit = $abn[$position] - ($position ? 0 : 1);$sum += $weight * $digit;}return ($sum % 89)==0;}return false;}public static function ABNLookup($abn){try{$abnLookup = new \PPost\Library\ABNLookup();try{$result = $abnLookup->searchByAbn($abn);var_dump($result);//return $result->ABRPayloadSearchResults->response;return $result;} catch    (Exception $e){throw $e;}} catch(Exception $e){throw $e;}}
}