Function update

examples/hello-mui/js/mui.js:910–918

(fn)

            get: function() {
                var self = this;
                function update(fn) {
                    return function(value) {
                        var classes = self.className.split(/\s+/),
                                index = classes.indexOf(value);

                        fn(classes, index, value);
                        self.className = classes.join(" ");
                    };
                }

                var ret = {
                    add: update(function(classes, index, value) {