Javascript代码不仅在IE中工作

我刚刚验证了我的javascript代码在除IE以外的所有浏览器中都能正常工作。脚本怎么可能在Chrome，Safari中正确读取和执行...但是IE发现了一些莫名其妙的错误并拒绝运行代码？

$(document).ready(function() {
        var NewsNavigator = {
            init: function(config) {
                this.news = config.news;
                this.newsNum = this.news.length;
                this.navbuttons = config.navbuttons;
                this.prevButton = config.prevButton;
                this.nextButton = config.nextButton;
                this.displayatonce = config.displayatonce;
                this.maxSteps = Math.ceil(this.newsNum / this.displayatonce);
                this.counter = 0;
                this.navigateNews();
                this.enableNav();
                this.checkButtonsVisibility();
            },
            showNews: function() {
                var start = this.counter * this.displayatonce;
                var end = this.counter * this.displayatonce + (this.displayatonce - 1);
                for (i=start; i<=end; i++) {
                    this.news.eq(i).show();
                }
            },
            hideAllNews: function() {
                console.log("hiding news");
                this.news.hide();
            },
            navigateNews: function() {
                this.hideAllNews();
                this.showNews();
            },
            checkButtonsVisibility: function() {
                if (this.counter <= 0)
                {
                    this.prevButton.css('visibility', 'hidden');
                }
                else
                {
                    this.prevButton.css('visibility', 'visible');
                }
                if (this.counter >= this.maxSteps - 1) 
                {
                    this.nextButton.css('visibility', 'hidden');
                }
                else
                {
                    this.nextButton.css('visibility', 'visible');
                }
            },
            enableNav: function() {
                self = this;
                this.navbuttons.on('click', function(event) {
                    if (($(this).data('dir') === 'prev') && (self.counter > 0)) {
                        self.counter--;
                        self.navigateNews();
                    } else if (($(this).data('dir') === 'next') && (self.counter < self.maxSteps - 1)) {
                        self.counter++;
                        self.navigateNews();
                    }
                self.checkButtonsVisibility();
                event.preventDefault(); 
                });
            }
        };
        NewsNavigator.init({
            news: $('div#cat-news').find('div.oneCol'),
            displayatonce: 3,
            navbuttons: $('div#nav').find('a'),
            prevButton: $('div#nav a.prec'),
            nextButton: $('div#nav a.succ')
        });
});

IE9 中的错误消息

SCRIPT438: The object doesn't support the 'checkButtonsVisibility' property or method.
NewsNavigator.js, Row 69 Character 5