View file bootstrap/js/path.js

(function ($){
                $(function (){
                    $('.btn').each(function (){
                        var self = this;
                        $('input[type=file]', this).change(function (){
                            // remove existing file info
                            $(self).next().remove();
                            // get value
                            var value = $(this).val();
                            // get file name
                            var fileName = value.substring(value.lastIndexOf('/')+1);
                            // get file extension
                            var fileExt = fileName.split('.').pop().toLowerCase();
                            // append file info
                            $('<span><i class="icon-file icon-' + fileExt + '"></i> ' + fileName + '</span>').insertAfter(self);
                        });
                    });
                });
})(jQuery);