undefined % 4 > 0 is always false :)

`i` is undefined and `undefined % 4 > 0` is always false so this code will never throw an error, no matter how long will be the string.

```js
var i, l, tmp, hasPadding, arr = [];

if (i % 4 > 0) {
       throw 'Invalid string. Length must be a multiple of 4';
}
```

Regards,
Satanowski