next（）在向右滚动时有效，而prev（）在向左滚动时无效

Question

我正在移动网站上创建照片滑块。它具有用于向左和向右滚动的按钮。我的Jquery代码可以向右滚动，但不能向左滚动。

似乎在mobilePropertyPictureSlideLeft(mobileSlideArrow)中出现了问题，特别是在同时返回if且被视为0的{​​{1}}条件下。

我尝试使用false，但是特定功能永远无法使用。

prevAll().first()

function mobilePropertyPictureSlideRight(mobileSlideArrow) {
  var activeMobileSlidePaginationCirle = $(mobileSlideArrow).next('.mobile_property_display_picture_pagination').children('.mobile_property_display_picture_pagination_circle.active_mobile_property_display_picture_pagination_circle');
  if ($(activeMobileSlidePaginationCirle).next('.mobile_property_display_picture_pagination_circle').length) {
    $(activeMobileSlidePaginationCirle).removeClass('active_mobile_property_display_picture_pagination_circle');
    $(activeMobileSlidePaginationCirle).next('.mobile_property_display_picture_pagination_circle').addClass('active_mobile_property_display_picture_pagination_circle');
  }
  var activeMobileDisplayPicture = $(mobileSlideArrow).prev('.mobile_property_display_picture_container').children('.mobile_property_display_picture.mobile_property_display_picture_in_view');
  var mobilePropertyDisplayPictureContainer = $(mobileSlideArrow).prev('.mobile_property_display_picture_container');
  if ($(activeMobileDisplayPicture).next('.mobile_property_display_picture').length) {
    $(activeMobileDisplayPicture).removeClass('mobile_property_display_picture_in_view');
    $(activeMobileDisplayPicture).next('.mobile_property_display_picture').addClass('mobile_property_display_picture_in_view');
    $(mobilePropertyDisplayPictureContainer).animate({
      scrollLeft: $(mobilePropertyDisplayPictureContainer).scrollLeft() + $(activeMobileDisplayPicture).outerWidth()
    }, 400);
  }
}

function mobilePropertyPictureSlideLeft(mobileSlideArrow) {
  var activeMobileSlidePaginationCirle = $(mobileSlideArrow).next('.mobile_property_display_picture_pagination').children('.mobile_property_display_picture_pagination_circle.active_mobile_property_display_picture_pagination_circle');
  if ($(activeMobileSlidePaginationCirle).prev('.mobile_property_display_picture_pagination_circle').length) {
    $(activeMobileSlidePaginationCirle).removeClass('active_mobile_property_display_picture_pagination_circle');
    $(activeMobileSlidePaginationCirle).prev('.mobile_property_display_picture_pagination_circle').addClass('active_mobile_property_display_picture_pagination_circle');
  }
  var activeMobileDisplayPicture = $(mobileSlideArrow).prev('.mobile_property_display_picture_container').children('.mobile_property_display_picture.mobile_property_display_picture_in_view');
  var mobilePropertyDisplayPictureContainer = $(mobileSlideArrow).prev('.mobile_property_display_picture_container');
  if ($(activeMobileDisplayPicture).prev('.mobile_property_display_picture').length) {
    $(activeMobileDisplayPicture).removeClass('mobile_property_display_picture_in_view');
    $(activeMobileDisplayPicture).prev('.mobile_property_display_picture').addClass('mobile_property_display_picture_in_view');
    $(mobilePropertyDisplayPictureContainer).animate({
      scrollLeft: $(mobilePropertyDisplayPictureContainer).scrollLeft() - $(activeMobileDisplayPicture).outerWidth()
    }, 400);
  }
}