js/filter: Fix passing null to selectCat() in IE
js/filter: Fix passing null to selectCat() in IE

Apparently IE doesn't like it when you put a HTMLCollection object
inside a DOM value.

erengy/vndb,morkt/vndb,morkt/vndb,erengy/vndb,morkt/vndb,christian-roggia/vndb,morkt/vndb,erengy/vndb,christian-roggia/vndb,christian-roggia/vndb,morkt/vndb