我只有在這個class中沒有none的時候才會出現(xiàn)二級菜單，有none就會出來一個細(xì)一點的框，<div id="sub" class=""> <div id="a" class="sub_content" >
<body>
?? ??? ?<div class="wrap" id="test">
?? ??? ??? ?<ul>
?? ??? ??? ??? ?<li data-id="a">
?? ??? ??? ??? ??? ?<span>家用電器</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "b">
?? ??? ??? ??? ??? ?<span>手機(jī) /運營商 /數(shù)碼</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id ="c">
?? ??? ??? ??? ??? ?<span>電腦辦公</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id ="d">
?? ??? ??? ??? ??? ?<span>家具 /家居 /家裝 /廚具</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id ="e">
?? ??? ??? ??? ??? ?<span>男裝 /女裝 /童裝 /內(nèi)衣</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "f">
?? ??? ??? ??? ??? ?<span>化妝品 /清潔用品 /寵物</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "g">
?? ??? ??? ??? ??? ?<span>鞋靴 /箱包 /珠寶 /奢侈品</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li? data-id = "h">
?? ??? ??? ??? ??? ?<span>運動 /戶外 /鐘表</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "i">
?? ??? ??? ??? ??? ?<span>汽車 /汽車用品</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "j">
?? ??? ??? ??? ??? ?<span>女嬰 /玩具樂器</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?<li data-id = "k">
?? ??? ??? ??? ??? ?<span>食品 /酒類 /生鮮 /特產(chǎn)</span>
?? ??? ??? ??? ?</li>
?? ???????????? <li data-id = "l">
?? ??? ??? ??? ??? ?<span>醫(yī)藥保健</span>
?? ??? ??? ??? ?</li>
?? ??? ??? ??? ?
?? ??? ??? ?</ul>
?? ??? ??? ?<div id="sub" class="">
?? ??? ??? ??? ?<div id="a" class="sub_content" >
?? ??? ??? ??? ??? ?<dl>
?? ??? ??? ??? ??? ??? ?<dt>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">電視<i>></i></a>
?? ??? ??? ??? ??? ??? ?</dt>
?? ??? ??? ??? ??? ??? ?<dd class="first">
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">合資品牌</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">國產(chǎn)品牌</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">互聯(lián)網(wǎng)品牌</a>
?? ??? ??? ??? ??? ??? ?</dd>
?? ??? ??? ??? ??? ?</dl>?? ?
?? ??? ??? ??? ??? ?<dl>
?? ??? ??? ??? ??? ??? ?<dt>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">空調(diào)<i>></i></a>
?? ??? ??? ??? ??? ??? ?</dt>
?? ??? ??? ??? ??? ??? ?<dd>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">壁掛式空調(diào)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">柜式空調(diào)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">中央空調(diào)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">空調(diào)配件</a>
?? ??? ??? ??? ??? ??? ?</dd>
?? ??? ??? ??? ??? ?</dl>
?? ??? ??? ??? ??? ?<dl>
?? ??? ??? ??? ??? ??? ?<dt>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">洗衣機(jī)<i>></i></a>
?? ??? ??? ??? ??? ??? ?</dt>
?? ??? ??? ??? ??? ??? ?<dd>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">滾筒洗衣機(jī)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">洗烘一體機(jī)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">波輪洗衣機(jī)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">迷你洗衣機(jī)</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">洗衣機(jī)配件</a>
?? ??? ??? ??? ??? ??? ?</dd>
?? ??? ??? ??? ??? ?</dl>
?? ??? ??? ??? ??? ?<dl>
?? ??? ??? ??? ??? ??? ?<dt>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">冰箱<i>></i></a>
?? ??? ??? ??? ??? ??? ?</dt>
?? ??? ??? ??? ??? ??? ?<dd>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">多門</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">對開門</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">三門</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">雙門</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">冷柜/冰吧</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">酒柜</a>
?? ??? ??? ??? ??? ??? ??? ?<a href="#" target="_blank">冰箱配件</a>
?? ??? ??? ??? ??? ??? ?</dd>
?? ??? ??? ??? ??? ?</dl>
?? ??? ??? ??? ??? ?
?? ??? ??? ??? ?</div>
?? ??? ??? ?</div>
?? ??? ?</div>
2020-04-23
class的名字none取什么不重要，重要的是在這個類中有：display;none;