Only works in firefox (!)

JavaScript
1

hi

i am trying this code, but only works in firefox

What is the problem?

[URL=“http://jsfiddle.net/mWHZ4/”]
DEMO


$(".mydds").msDropDown();
        $('#adicionar').click (function(){
            var num = $('.linguas').length;
            var newNum = new Number(num + 1);
            
            var newElem = $('#copiar' + num).clone(true, true).attr('id', 'copiar' + newNum);
            
            var id = newElem.find('select').msDropDown().data('dd').get('id');
            
            newElem.html(newElem.html().replace(id,'customid_' + newNum,'g'));
            
            $('#copiar' + num).after(newElem);

            newElem.find('select').msDropDown();
        });

thanks