JS Verification ID Number

--Identification number verification-support for new X ID card
function Isidcardno (num)
{
var Factorarr = new Array (7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2,1);
var error;
var vararray = new Array ();
var intvalue;
var lngproduct = 0;
var intcheckdigit;
var intstrlen = num.length;
var idNumber = num;
Initialize
if ((Intstrlen!=) && (Intstrlen!= 18)) {
Error = "Input ID number length is not correct!" ";
alert (error);
FrmAddUser.txtIDCard.focus ();
return false;
}
Check and set value
for (i=0;i<intstrlen;i++) {
Vararray[i] = Idnumber.charat (i);
if ((Vararray[i] < ' 0 ' vararray[i] > ' 9 ') && (i!= 17)) {
Error = "Wrong ID number!.";
alert (error);
FrmAddUser.txtIDCard.focus ();
return false;
else if (I < 17) {
Vararray[i] = Vararray[i]*factorarr[i];
}
}
if (Intstrlen = = 18) {
Check Date
var Date8 = idnumber.substring (6,14);
if (checkdate (date8) = = False) {
Error = "The date information in the ID card is incorrect!.";
alert (error);
return false;
}
Calculate the sum of the products
for (i=0;i<17;i++) {
Lngproduct = lngproduct + vararray[i];
}
Calculate the check digit
Intcheckdigit = 12-lngproduct% 11;
Switch (intcheckdigit) {
Case 10:
Intcheckdigit = ' X ';
Break
Case 11:
Intcheckdigit = 0;
Break
Case 12:
Intcheckdigit = 1;
Break
}
Check last digit
if (Vararray[17].touppercase ()!= intcheckdigit) {
Error = "id parity bit wrong!... Correct for: "+ Intcheckdigit +".
alert (error);
return false;
}
}
else{//length is 15
Check Date
var date6 = idnumber.substring (6,12);
if (checkdate (date6) = = False) {
Alert ("ID date information is incorrect!.");
return false;
}
}
Alert ("correct.");
return true;
}