Get the value from the last character to left.

Hey, the title might seem a little confusing, but an example can make it very clear. Let's say I have the following pattern:

``` js
var mask = new InputMask({pattern: '11/11/1111'});

mask.paste('111');
```

If I use the `getValue` method, I get the string `'11/1_/____'`.

Is there a way to get only the characters from the last 1 to the left? it would return something like this: `11/1`

thanks.