Javascript error if Views Selective Filter module removes all checkboxes

If BEF is enabled with the Views Selective Filter module, removing all checkboxes from an exposed filter (as a result of the Selective Filter) causes a Javascript error. This assumes you have more than one exposed filter.

The root cause is with the slice method on 336 of better_exposed_filters.js:

var $filter_name = $('input', this).attr('name').slice(0, -2);

The input wouldn't exist in this case so we need to check if there is one.