isChecksumAddress = function (address) {    
    // Check each case
    address = address.replace('0x','');
    var addressHash = sha3(address.toLowerCase()).toString('hex');
    for (var i = 0; i < 40; i++ ) { 
        // the nth letter should be uppercase if the nth digit of casemap is 1
        if ((parseInt(addressHash[i], 16) > 7 && address[i].toUpperCase() !== address[i]) || (parseInt(addressHash[i], 16) <= 7 && address[i].toLowerCase() !== address[i])) {
            return false;
        }
    }
    return true;    
}
Checks if the given string is a checksummed address

@method isChecksumAddress
@param {String} address the given HEX adress
@return {Boolean}