极客观点
项目管理
HarmonyOS
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<div class="title">手机、配件</div>
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<span class="bold mr10">手机通讯：</span>
<a href="">手机</a>
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<a href="">手机维修</a>
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<a href="">以旧换新</a>
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<span class="bold mr10">手机配件：</span>
<a href="">手机壳</a>
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<a href="">手机存储卡</a>
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<a href="">数据线</a>
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<a href="">充电器</a>
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<a href="">电池</a>
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<span class="bold mr10">运营商：</span>
<a href="">中国联通</a>
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<a href="">中国电信</a>
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<span class="bold mr10">智能设备：</span>
<a href="">智能手环</a>
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<a href="">智能家居</a>
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<a href="">智能手表</a>
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<a href="">其他配件</a>
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<span class="bold mr10">娱乐：</span>
<a href="">耳机</a>
<span class="ml10 mr10">/</span>
<a href="">音响</a>
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<a href="">收音机</a>
<span class="ml10 mr10">/</span>
<a href="">麦克风</a>
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<div class="title">电脑</div>
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<span class="bold mr10">电脑：</span>
<a href="">笔记本</a>
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<a href="">平板</a>
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<a href="">一体机</a>
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<span class="bold mr10">电脑配件：</span>
<a href="">显示器</a>
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<a href="">CPU</a>
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<a href="">主板</a>
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<a href="">硬盘</a>
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<a href="">电源</a>
<span class="ml10 mr10">/</span>
<a href="">显卡</a>
<span class="ml10 mr10">/</span>
<a href="">其他配件</a>
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<span class="bold mr10">游戏设备：</span>
<a href="">游戏机</a>
<span class="ml10 mr10">/</span>
<a href="">耳机</a>
<span class="ml10 mr10">/</span>
<a href="">游戏软件</a>
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<span class="bold mr10">网络产品：</span>
<a href="">路由器</a>
<span class="ml10 mr10">/</span>
<a href="">网络机顶盒</a>
<span class="ml10 mr10">/</span>
<a href="">交换机</a>
<span class="ml10 mr10">/</span>
<a href="">存储卡</a>
<span class="ml10 mr10">/</span>
<a href="">网卡</a>
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<span class="bold mr10">外部产品：</span>
<a href="">鼠标</a>
<span class="ml10 mr10">/</span>
<a href="">键盘</a>
<span class="ml10 mr10">/</span>
<a href="">U盘</a>
<span class="ml10 mr10">/</span>
<a href="">移动硬盘</a>
<span class="ml10 mr10">/</span>
<a href="">鼠标垫</a>
<span class="ml10 mr10">/</span>
<a href="">电脑清洁</a>
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<div class="title">家用电器</div>
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<span class="bold mr10">电视：</span>
<a href="">国产品牌</a>
<span class="ml10 mr10">/</span>
<a href="">韩国品牌</a>
<span class="ml10 mr10">/</span>
<a href="">欧美品牌</a>
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<span class="bold mr10">空调：</span>
<a href="">显示器</a>
<span class="ml10 mr10">/</span>
<a href="">柜式</a>
<span class="ml10 mr10">/</span>
<a href="">中央</a>
<span class="ml10 mr10">/</span>
<a href="">壁挂式</a>
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<span class="bold mr10">冰箱：</span>
<a href="">多门</a>
<span class="ml10 mr10">/</span>
<a href="">对开门</a>
<span class="ml10 mr10">/</span>
<a href="">三门</a>
<span class="ml10 mr10">/</span>
<a href="">双门</a>
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<span class="bold mr10">洗衣机：</span>
<a href="">滚筒式洗衣机</a>
<span class="ml10 mr10">/</span>
<a href="">迷你洗衣机</a>
<span class="ml10 mr10">/</span>
<a href="">洗烘一体机</a>
</div>
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<span class="bold mr10">厨房电器：</span>
<a href="">油烟机</a>
<span class="ml10 mr10">/</span>
<a href="">洗碗机</a>
<span class="ml10 mr10">/</span>
<a href="">燃气灶</a>
</div>
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<div class="title">家具</div>
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<span class="bold mr10">家纺：</span>
<a href="">被子</a>
<span class="ml10 mr10">/</span>
<a href="">枕头</a>
<span class="ml10 mr10">/</span>
<a href="">四件套</a>
<span class="ml10 mr10">/</span>
<a href="">床垫</a>
</div>
<div class="sub-row">
<span class="bold mr10">灯具：</span>
<a href="">台灯</a>
<span class="ml10 mr10">/</span>
<a href="">顶灯</a>
<span class="ml10 mr10">/</span>
<a href="">节能灯</a>
<span class="ml10 mr10">/</span>
<a href="">应急灯</a>
</div>
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<span class="bold mr10">厨具：</span>
<a href="">烹饪锅具</a>
<span class="ml10 mr10">/</span>
<a href="">餐具</a>
<span class="ml10 mr10">/</span>
<a href="">菜板刀具</a>
</div>
<div class="sub-row">
<span class="bold mr10">家装：</span>
<a href="">地毯</a>
<span class="ml10 mr10">/</span>
<a href="">沙发垫套</a>
<span class="ml10 mr10">/</span>
<a href="">装饰字画</a>
<span class="ml10 mr10">/</span>
<a href="">照片墙</a>
<span class="ml10 mr10">/</span>
<a href="">窗帘</a>
</div>
<div class="sub-row">
<span class="bold mr10">生活日用：</span>
<a href="">收纳用品</a>
<span class="ml10 mr10">/</span>
<a href="">浴室用品</a>
<span class="ml10 mr10">/</span>
<a href="">雨伞雨衣</a>
</div>
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</html>
var index = 0,
timer = null,
banner= byId("banner").getElementsByTagName("div"),
dots = byId("dots").getElementsByTagName("span"),
len = banner.length,
prev = byId("prev"),
next = byId("next"),
menu = byId("menu-content"),
subMenu = byId("sub-menu"),
innerBox = subMenu.getElementsByClassName("inner-box"),
menuItems = menu.getElementsByClassName("menu-item");
你menu-content是通过id获取到的,在dom中没有id为menu-content的,好像还有其它的几个你也获取错了