public function validateIBAN(iban:String):Boolean
{
    var nums:Object     = { A:10, B:11, C:12, D:13, E:14,
                    F:15, G:16, H:17, I:18, J:19,
                    K:20, L:21, M:22, N:23, O:24,
                    P:25, Q:26, R:27, S:28, T:29,
                    U:30, V:31, W:32, X:33, Y:34, Z:35 };
    var chars:Array     = iban.split('');
 
    for (var i:int = 0; i < 4; i++)
    {
        chars.push(chars.shift());
    }
 
    var exp:RegExp = /[a-z]/i;
    for (var j:int = 0; j < chars.length; j++)
    {
        chars[j] = exp.test(chars[j]) ? nums[chars[j].toUpperCase()] : chars[j];
    }
    iban = chars.join('');
    return modulus(iban, 97) == 1;
}

public function modulus(largeNumber:String, mod:uint):Number
{
    var tmp:String      = largeNumber.substr(0, 10);
    var number:String   = largeNumber.substr(tmp.length);
    var result:String;
 
    do {
        result = String(Number(tmp) % mod);
        number = result + number;
        tmp = number.substr(0, 10);
        number = number.substr(tmp.length);
 
    } while (number.length > 0);
 
    return Number(tmp) % mod;
}

public function validateIBAN(iban:String):Boolean
{
    var nums:Object     = { A:10, B:11, C:12, D:13, E:14,
                    F:15, G:16, H:17, I:18, J:19,
                    K:20, L:21, M:22, N:23, O:24,
                    P:25, Q:26, R:27, S:28, T:29,
                    U:30, V:31, W:32, X:33, Y:34, Z:35 };
    var chars:Array     = iban.split('');
 
    for (var i:int = 0; i < 4; i++)
    {
        chars.push(chars.shift());
    }
 
    var exp:RegExp = /[a-z]/i;
    for (var j:int = 0; j < chars.length; j++)
    {
        chars[j] = exp.test(chars[j]) ? nums[chars[j].toUpperCase()] : chars[j];
    }
    iban = chars.join('');
    return modulus(iban, 97) == 1;
}

http://active.tutsplus.com/tutorials/actionscript/validating-various-input-data-in-flash/

From the tutorial, Validating Various Input Data in Flash (http://active.tutsplus.com/tutorials/actionscript/validating-various-input-data-in-flash/)

Validate IBAN with RegExp

regexp, validation

ActionScript 3