老师问下问题

来源：3-5 让菜单下拉

vivi_li

2020-05-25 10:36:42

为什么鼠标移入tropdown的时候布局会变动

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>慕淘网</title>
<link rel="stylesheet" href="css/base.css">
<link rel="stylesheet" href="css/common.css">
<link rel="stylesheet" href="css/index.css">
</head>
<body>

<div class="nav-site">
<div class="container">
<ul class="fl">
<li class="fl"><a href="javascript:;" class="nav-site-login">亲，请登录</a></li>
<li class="fl"><a href="javascript:;" class="nav-site-signup link">免费注册</a></li>
<li class="fl"><a href="###" target="_blank" class="nav-site-mobile link">手机逛慕淘</a></li>
</ul>
<ul class="fr">
<li class="fl dropdown">
<a href="###" target="_blank" class="dropdown-toggle link">我的慕淘 <i class="dropdown-arrow"></i></a>
<ul class="dropdown-layer dropdown-left">
<li><a href="###" target="_blank" class="dropdown-item">已买到的宝贝</a></li>
<li><a href="###" target="_blank" class="dropdown-item">我的足迹</a></li>
</ul>
</li>
<li class="fl dropdown">
<a href="###" target="_blank" class="dropdown-toggle link">收藏夹 <i class="dropdown-arrow"></i></a>
<ul class="dropdown-layer dropdown-left">
<li><a href="###" target="_blank" class="dropdown-item">收藏的宝贝</a></li>
<li><a href="###" target="_blank" class="dropdown-item">收藏的店铺</a></li>
</ul>
</li>
<li class="fl">
<a href="###" target="_blank" class="nav-site-category link">商品分类</a>
</li>
<li class="fl dropdown">
<a href="###" target="_blank" class="dropdown-toggle link">卖家中心 <i class="dropdown-arrow"></i></a>
<ul class="dropdown-layer dropdown-left">
<li><a href="###" target="_blank" class="dropdown-item">免费开店</a></li>
<li><a href="###" target="_blank" class="dropdown-item">已卖出的宝贝</a></li>
<li><a href="###" target="_blank" class="dropdown-item">出售中的宝贝</a></li>
<li><a href="###" target="_blank" class="dropdown-item">卖家服务市场</a></li>
<li><a href="###" target="_blank" class="dropdown-item">卖家培训中心</a></li>
<li><a href="###" target="_blank" class="dropdown-item">体验中心</a></li>
</ul>
</li>
<li class="nav-site-service fl dropdown">
<a href="###" target="_blank" class="dropdown-toggle link">联系客服 <i class="dropdown-arrow"></i></a>
<ul class="dropdown-layer dropdown-right">
<li><a href="###" target="_blank" class="dropdown-item">消费者客服</a></li>
<li><a href="###" target="_blank" class="dropdown-item">卖家客服</a></li>
</ul>
</li>
</ul>
</div>
</div>
</body>

<script src='plug/jQ/jQuery3.5.1.js'></script>
<script src="js/index.js"></script>
</html>

/*nav-site*/
.nav-site{
width: 100%;
background-color: #f3f5f7;
}
.nav-site .container{
height: 44px;
line-height: 44px;
border-bottom: 1px solid #cdd0d4;
}
.nav-site-login{
color: #f01414;
margin-left: 15px;
}
.nav-site-signup,
.nav-site-mobile{
margin-left: 10px;
}
.nav-site-category{
margin: 0 10px;
}
.nav-site-service{
margin-right: 15px;
}
/*dropdown*/
.dropdown{
position: relative;
}
.dropdown-toggle{
/*position: relative;*/
/*z-index: 2;*/
display: block;
height: 100%;
padding: 0 16px 0 12px;
border-left: 1px solid #f3f5f7;/*需要设置边框，但是跟背景颜色一样，否则hover的时候布局会变动*/
border-right: 1px solid #f3f5f7;
}
.dropdown-arrow{
display: inline-block;
width: 8px;
height: 6px;
background: url(../img/dropdown-arrow.png) no-repeat;
margin-left: 8px;
vertical-align: middle;
}
.dropdown-layer{
/*z-index: 1;*/
display: none;
position: absolute;
top: 43px;
background-color: #fff;
border: 1px solid #cdd0d4;
/*white-space: nowrap;!*不换行*!*/
border-top: none;
}
.dropdown-left{
left: 0;
right: auto;

}
.dropdown-right{
right: 0;
left: auto;
}
.dropdown-item{
display: block;
color: #4d555d;
padding: 0 12px;
height: 30px;
line-height: 30px;
white-space: nowrap;/*不换行*/
}
.dropdown-item:hover{
background-color: #f3f5f7;
}
.dropdown-active .dropdown-toggle,
.dropdown:hover .dropdown-toggle{
border-color: #cdd0d4;
background-color: #fff;
}
.dropdown-active .dropdown-arrow,
.dropdown:hover .dropdown-arrow{
background-image: url(../img/dropdown-arrow-active.png);
}
.dropdown-active .dropdown-layer,
.dropdown:hover .dropdown-layer{
display: block;
}