Example js code to validate Iran's National ID also known as the Code Melli – کد نمونه جاوا اسکریپت برای بررسی صحت و تأیید کد ملی.

validateNID.js

/**
 * Example Javascript snippet to validate Iran's National ID (Code Melli)
 * https://math.stackexchange.com/q/2740295/285467
 * David Refoua <David@Refoua.me>
 */
function validateNID( code )
{
    var str = code.toString();

    // validate the string length and value
    var strLen = str.length, strVal = parseInt(str);
    if ( strLen < 8 || strLen > 10 || isNaN(strVal) || strVal == 0 )
        return false;
    
    // make sure the string is padded with zeros
    while ( str.length < 10 ) str = '0' + str;
    
    // invalidate consecutive arrangement of the same digit
    if ( str.match(/^(\d)\1+$/g) ) return false;
    
    var checkDigit = parseInt(str.slice(-1)), // rightmost digit
        str = str.slice(0, -1); // remove the check digit
        
    for ( var sum = 0, i = str.length; i > 0; i-- )
        sum += (i+1) * str.substr( -i, 1 );
    
    // calculate sum modulo 11
    var mod = sum % 11;
        
    return ( mod < 2 && mod === checkDigit ) || ( mod >= 2 && mod + checkDigit === 11);
    
}