ü becomes u
ó becomes o
I'd rather not use a replace, because a) it requires a complete set of characters, which is a lot of work and b) i'd would be hard to get a complete set of characters, and i'll never be certain if i'm missing one or two.
As @Pointy said, your only option is to map/replace characters according to a dictionary.
You'll find this really useful: https://github.com/backbone-paginator/backbone.paginator/blob/a579796a30e583c4dfa09e0a86e4abd21e0b5b56/plugins/diacritic.js