javascript Verifying the Format or Authenticity of Hong Kong Identity Card

Not much to say, please look at the code

function IsHKID(str) {
 var strValidChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 // basic check length
 if (str.length < 8)
 return false;
 // handling bracket
 if (str.charAt(str.length-3) == '(' && str.charAt(str.length-1) == ')')
 str = str.substring(0, str.length - 3) + str.charAt(str.length -2);
 // convert to upper case
 str = str.toUpperCase();
 // regular expression to check pattern and split
 var hkidPat = /^([A-Z]{1,2})([0-9]{6})([A0-9])$/;
 var matchArray = str.match(hkidPat);
 // not match, return false
 if (matchArray == null)
 return false;
 // the character part, numeric part and check digit part
 var charPart = matchArray[1];
 var numPart = matchArray[2];
 var checkDigit = matchArray[3];
 // calculate the checksum for character part
 var checkSum = 0;
 if (charPart.length == 2) {
 checkSum += 9 * (10 + strValidChars.indexOf(charPart.charAt(0)));
 checkSum += 8 * (10 + strValidChars.indexOf(charPart.charAt(1)));
 } else {
 checkSum += 9 * 36;
 checkSum += 8 * (10 + strValidChars.indexOf(charPart));
 }
 // calculate the checksum for numeric part
 for (var i = 0, j = 7; i < numPart.length; i++, j--)
 checkSum += j * numPart.charAt(i);
 // verify the check digit
 var remaining = checkSum % 11;
 var verify = remaining == 0 ? 0 : 11 - remaining;
 return verify == checkDigit || (verify == 10 && checkDigit == 'A');
}

After searching for a long time on the Internet, I didn't have a satisfactory verification method. Finally, I found an js verification written abroad through Google, and found that it can be used.

The above section is very precise, including the verification of the authenticity of the ID card. If you only want to verify the format of the entered Hong Kong ID card, please use the following section js.

function IsHKID(str) {
 var strValidChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 // basic check length
 if (str.length < 8)
 return false;
 // handling bracket
 if (str.charAt(str.length-3) == '(' && str.charAt(str.length-1) == ')')
 str = str.substring(0, str.length - 3) + str.charAt(str.length -2);
 // convert to upper case
 str = str.toUpperCase();
 // regular expression to check pattern and split
 var hkidPat = /^([A-Z]{1,2})([0-9]{6})([A0-9])$/;
 var matchArray = str.match(hkidPat);
 // not match, return false
 if (matchArray == null)
 return false;
 return true;
 }