jquery mobile select-menu-custom-filter portuguese language

jquery mobile select-menu-custom-filter portuguese language

Hi, 

I am a novice and trying to get my head arround jquery.I am testing a jquery mobile filterable costum select in my project http://www.promocaototal.pt/cidades1.php it's all working fine but the issue is that the cities names are in Portuguese and when applying the filter it does not recognize the special charactes returning an empty search for names like Águeda when typing Agueda. Can anyone one point me in the right direction please?

Thanks