HTML 5 导航菜单

Question

这是我的 HTML5 导航栏。但是，子菜单不会隐藏，菜单也不会水平显示。国内、美国和国外以及顶级菜单选项和速度、可用性和价格是子菜单。但是 Foriegn 显示在下方而不是 American 旁边。提前谢谢你。

<nav>
  <ul class="topmenu">
  <li> <a href="index.html">Home</a></li>
  <li><a href="american.html">American</a></li>
    <ul class="submenu">
    <li> <a href="index.html">Speed</a></li>
    <li> <a href="index.html">Price</a></li>
    <li> <a href="index.html">Usability</a></li>
    </ul>
  <li><a href="foreign.html">Foreign</a></li>
    <ul class="submenu">
    <li> <a href="index.html">Speed</a></li>
    <li> <a href="index.html">Price</a></li>
    <li> <a href="index.html">Usability</a></li>
    </ul>
  </ul>
</nav>

CSS

nav{
    position: relative;
    background-color: #00baff;
    width: 50%;
    margin-left: auto;
    margin-right: auto;
}
.topmenu li{
    position: relative;
    list-style-type: none;
    font-size: 20px;
    display: inline-block;
    margin-right: 30px;
    color: white;
}
.topmenu li a{
    padding: 5px;
}
.topmenu a:link{
    text-decoration: none;
    color: #ffffff;
}
.topmenu a:visited{
    text-decoration: none;
    color: white;
}
.topmenu a:hover{
    background-color: #ffffff;
}
.topmenu li .submenu li{
    display: none;
    list-style-type: none;
}
.topmenu li:hover .submenu li{
    display: block;
    position: relative;
}

Fiddle

Answer 1

已解决:

CSS:

nav{
position: relative;
background-color: #00baff;
width: 50%;
margin-left: auto;
margin-right: auto;
}
/* This is your main UL resize to fit */
.topmenu{
width: 100%;    
height: 150px;
}
/* I used > li to target all elements of .topmenu */
.topmenu > li{
font-size: 20px;
margin-right: 10px;
color: white;
list-style:none;
display:inline;
float: left;
}
.topmenu > li a{
padding: 5px;
}
.topmenu a:link{
text-decoration: none;
color: #ffffff;
}
.topmenu a:visited{
text-decoration: none;
color: white;
}
.topmenu a:hover{
background-color: #ffffff;
}


/* new code 
 What this does is it targets all child UL elements on li:hover
  if they have them they will become VISIBLE if not nothing happens */
.topmenu > li:hover >ul{
visibility:visible;
}

/* your two sub menus set to hidden */
.american-submenu{
visibility:hidden;
}
.foreign-submenu{
visibility:hidden;
}

HTML

<nav>
<ul class="topmenu">
<li> <a href="index.html">Home</a></li>
<li><a href="american.html">American</a>
<ul class="american-submenu">
        <li> <a href="index.html">Speed</a></li>
        <li> <a href="index.html">Price</a></li>
        <li> <a href="index.html">Usability</a></li>
    </ul>
</li>
<li><a href="foreign.html">Foreign</a>
 <ul class="foreign-submenu">
            <li> <a href="index.html">Speed</a></li>
            <li> <a href="index.html">Price</a></li>
            <li> <a href="index.html">Usability</a></li>
     </ul>
</li>
</ul>
</nav>