TypeError: undefined is not an object error

Question

我有这段代码，它抛出一个 TypeError。我找不到问题所在。

代码

/ Topic Banners - swap out mobile ads
if ($('#advertisment-main').length){
    if (matchMedia('(min-width: 768px)').matches) {
    var topicBannerName = $('.topic-banner[src*="mobile"]').attr('src').replace('mobile.jpg','');
    $('.topic-banner').attr('src', topicBannerName + 'tablet.jpg');
    } else{
        var topicBannerName = $('.topic-banner[src*="tablet"]').attr('src').replace('tablet.jpg','');
        $('.topic-banner').attr('src', topicBannerName + 'mobile.jpg');
    }
}

错误

TypeError: undefined is not an object (evaluating '$('.topic-banner[src*="tablet"]').attr("src").replace')

Answer 1

那是因为您的选择器 $('.topic-banner[src*="tablet"]') 不匹配任何元素。确保选择器和 HTML 代码正确。

TypeError: undefined is not an object error

TypeError: undefined is not an object error

javascript

jquery

undefined

typeerror