Javascript 如何更改下拉列表的样式

Javascript 如何更改下拉列表的样式,javascript,css,html,Javascript,Css,Html,你好。我有一个一分为二的导航。一个在右边,一个在左边。我想更改右侧下拉列表的位置,以便在此处显示导航的所有内容是我的代码 <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <meta name="viewport" content="width=device-width,initial-scale=1.0" /> <title>Tanauan L

你好。我有一个一分为二的导航。一个在右边,一个在左边。我想更改右侧下拉列表的位置,以便在此处显示导航的所有内容是我的代码

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
<title>Tanauan LGU </title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>

<header>
    <img src="estate_banner.png" id="logo">
</header>
<nav>
<div id="menu">
  <ul>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
         </ul>
    </li>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
        </ul>
    </li>
    <li class="last"><a href="#">Welcome Admin</a>
         <ul>
          <li><a href="#">Subitem One</a></li>
          <li><a href="#">Subitem Two</a></li>
          <li><a href="#">Subitem Three</a> </li>
        </ul>      
    </li>
  </ul>
 </div>
</nav>
<body marginheight="0">
</body >
</html>

CSS:
 header{
  height:80px;
  width:100%;
  background: -webkit-linear-gradient(160deg,white, orange); /* For Safari 5.1 to 6.0  */
  background: -o-linear-gradient(180deg,white, orange); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg,white, orange); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg,white, orange); /* Standard syntax (must be last) */   }
#logo{margin-top:13px;}
#menu {
  background:#000;
  width:100%;
  height:40px;
  border-radius: 3px;
  float:left;
}
#menu ul ul {
  display: none;
}
#menu ul li:hover > ul {
  display: block;
}
#menu ul {
  padding: 0px;
  border-radius: 5px;
  list-style: none;
  margin:0;
  position: relative;
  display: block;
}
#menu ul:after {
  content:"";
  clear: both;
  display: block;
}
#menu ul li {
  float: left;
}
#menu ul li:hover {
  color:#fff;
}
#menu ul li:hover a {
  background:#fff;
  color: #000;
}
#menu ul li a {
  display: block;
  padding:0 10px;
  color: #FFF;
  text-decoration: none;
  line-height:40px;
}
#menu ul ul {
  background: #fff;
  padding:0;
  position: absolute;
  top: 40px;
  box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
}
#menu ul ul li {
  float: none;
  position: relative;
}
#menu ul ul li a {
  padding: 15px 40px;
  color: #fff;
  width:150px;
  height:50px;
}
#menu ul ul li a:hover {
  background: #000;
  color:#fff;
}
 #menu ul li.last {
   float:right;
}
HTML:

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
<title>Tanauan LGU </title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>

<header>
    <img src="estate_banner.png" id="logo">
</header>
<nav>
<div id="menu">
  <ul>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
         </ul>
    </li>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
        </ul>
    </li>
    <li class="last"><a href="#">Welcome Admin</a>
         <ul>
          <li><a href="#">Subitem One</a></li>
          <li><a href="#">Subitem Two</a></li>
          <li><a href="#">Subitem Three</a> </li>
        </ul>      
    </li>
  </ul>
 </div>
</nav>
<body marginheight="0">
</body >
</html>

CSS:
 header{
  height:80px;
  width:100%;
  background: -webkit-linear-gradient(160deg,white, orange); /* For Safari 5.1 to 6.0  */
  background: -o-linear-gradient(180deg,white, orange); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg,white, orange); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg,white, orange); /* Standard syntax (must be last) */   }
#logo{margin-top:13px;}
#menu {
  background:#000;
  width:100%;
  height:40px;
  border-radius: 3px;
  float:left;
}
#menu ul ul {
  display: none;
}
#menu ul li:hover > ul {
  display: block;
}
#menu ul {
  padding: 0px;
  border-radius: 5px;
  list-style: none;
  margin:0;
  position: relative;
  display: block;
}
#menu ul:after {
  content:"";
  clear: both;
  display: block;
}
#menu ul li {
  float: left;
}
#menu ul li:hover {
  color:#fff;
}
#menu ul li:hover a {
  background:#fff;
  color: #000;
}
#menu ul li a {
  display: block;
  padding:0 10px;
  color: #FFF;
  text-decoration: none;
  line-height:40px;
}
#menu ul ul {
  background: #fff;
  padding:0;
  position: absolute;
  top: 40px;
  box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
}
#menu ul ul li {
  float: none;
  position: relative;
}
#menu ul ul li a {
  padding: 15px 40px;
  color: #fff;
  width:150px;
  height:50px;
}
#menu ul ul li a:hover {
  background: #000;
  color:#fff;
}
 #menu ul li.last {
   float:right;
}

塔纳昂LGU
CSS: 标题{ 高度:80px; 宽度:100%; 背景:-webkit线性梯度(160度,白色,橙色);/*用于Safari 5.1至6.0*/ 背景:-o型线性梯度(180度,白色,橙色);/*用于Opera 11.1至12.0*/ 背景:-moz线性渐变(180度,白色,橙色);/*适用于Firefox 3.6至15*/ 背景:线性渐变(180度,白色,橙色);/*标准语法(必须是最后一个)*/} #徽标{页边距顶部:13px;} #菜单{ 背景:#000; 宽度:100%; 高度:40px; 边界半径:3px; 浮动:左; } #菜单{ 显示:无; } #菜单ul li:悬停>ul{ 显示:块; } #菜单ul{ 填充:0px; 边界半径:5px; 列表样式:无; 保证金:0; 位置:相对位置; 显示:块; } #菜单ul:之后{ 内容:“; 明确:两者皆有; 显示:块; } #菜单ulli{ 浮动:左; } #菜单:悬停{ 颜色:#fff; } #菜单ul li:将鼠标悬停在a上{ 背景:#fff; 颜色:#000; } #菜单ulli a{ 显示:块; 填充:0 10px; 颜色:#FFF; 文字装饰:无; 线高:40px; } #菜单{ 背景:#fff; 填充:0; 位置:绝对位置; 顶部:40px; 盒子阴影:0px 0px 9px rgba(0,0,0,0.15); } #菜单ul-li{ 浮动:无; 位置:相对位置; } #菜单ul li a{ 填充:15px 40px; 颜色:#fff; 宽度:150px; 高度:50px; } #菜单ul li a:悬停{ 背景:#000; 颜色:#fff; } #最后的菜单{ 浮动:对; }
更新的小提琴:

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
<title>Tanauan LGU </title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>

<header>
    <img src="estate_banner.png" id="logo">
</header>
<nav>
<div id="menu">
  <ul>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
         </ul>
    </li>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
        </ul>
    </li>
    <li class="last"><a href="#">Welcome Admin</a>
         <ul>
          <li><a href="#">Subitem One</a></li>
          <li><a href="#">Subitem Two</a></li>
          <li><a href="#">Subitem Three</a> </li>
        </ul>      
    </li>
  </ul>
 </div>
</nav>
<body marginheight="0">
</body >
</html>

CSS:
 header{
  height:80px;
  width:100%;
  background: -webkit-linear-gradient(160deg,white, orange); /* For Safari 5.1 to 6.0  */
  background: -o-linear-gradient(180deg,white, orange); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg,white, orange); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg,white, orange); /* Standard syntax (must be last) */   }
#logo{margin-top:13px;}
#menu {
  background:#000;
  width:100%;
  height:40px;
  border-radius: 3px;
  float:left;
}
#menu ul ul {
  display: none;
}
#menu ul li:hover > ul {
  display: block;
}
#menu ul {
  padding: 0px;
  border-radius: 5px;
  list-style: none;
  margin:0;
  position: relative;
  display: block;
}
#menu ul:after {
  content:"";
  clear: both;
  display: block;
}
#menu ul li {
  float: left;
}
#menu ul li:hover {
  color:#fff;
}
#menu ul li:hover a {
  background:#fff;
  color: #000;
}
#menu ul li a {
  display: block;
  padding:0 10px;
  color: #FFF;
  text-decoration: none;
  line-height:40px;
}
#menu ul ul {
  background: #fff;
  padding:0;
  position: absolute;
  top: 40px;
  box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
}
#menu ul ul li {
  float: none;
  position: relative;
}
#menu ul ul li a {
  padding: 15px 40px;
  color: #fff;
  width:150px;
  height:50px;
}
#menu ul ul li a:hover {
  background: #000;
  color:#fff;
}
 #menu ul li.last {
   float:right;
}
在左侧下拉列表中添加了
left:0
,在右侧下拉列表中添加了
right:0

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
<title>Tanauan LGU </title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>

<header>
    <img src="estate_banner.png" id="logo">
</header>
<nav>
<div id="menu">
  <ul>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
         </ul>
    </li>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
        </ul>
    </li>
    <li class="last"><a href="#">Welcome Admin</a>
         <ul>
          <li><a href="#">Subitem One</a></li>
          <li><a href="#">Subitem Two</a></li>
          <li><a href="#">Subitem Three</a> </li>
        </ul>      
    </li>
  </ul>
 </div>
</nav>
<body marginheight="0">
</body >
</html>

CSS:
 header{
  height:80px;
  width:100%;
  background: -webkit-linear-gradient(160deg,white, orange); /* For Safari 5.1 to 6.0  */
  background: -o-linear-gradient(180deg,white, orange); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg,white, orange); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg,white, orange); /* Standard syntax (must be last) */   }
#logo{margin-top:13px;}
#menu {
  background:#000;
  width:100%;
  height:40px;
  border-radius: 3px;
  float:left;
}
#menu ul ul {
  display: none;
}
#menu ul li:hover > ul {
  display: block;
}
#menu ul {
  padding: 0px;
  border-radius: 5px;
  list-style: none;
  margin:0;
  position: relative;
  display: block;
}
#menu ul:after {
  content:"";
  clear: both;
  display: block;
}
#menu ul li {
  float: left;
}
#menu ul li:hover {
  color:#fff;
}
#menu ul li:hover a {
  background:#fff;
  color: #000;
}
#menu ul li a {
  display: block;
  padding:0 10px;
  color: #FFF;
  text-decoration: none;
  line-height:40px;
}
#menu ul ul {
  background: #fff;
  padding:0;
  position: absolute;
  top: 40px;
  box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
}
#menu ul ul li {
  float: none;
  position: relative;
}
#menu ul ul li a {
  padding: 15px 40px;
  color: #fff;
  width:150px;
  height:50px;
}
#menu ul ul li a:hover {
  background: #000;
  color:#fff;
}
 #menu ul li.last {
   float:right;
}
HTML:

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
<title>Tanauan LGU </title>
<link href="styles.css" rel="stylesheet" type="text/css" />
</head>

<header>
    <img src="estate_banner.png" id="logo">
</header>
<nav>
<div id="menu">
  <ul>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
           <li><a href="#">item1</a> </li>
         </ul>
    </li>
    <li><a href="#">item1</a> </li>
    <li><a href="#">item1</a>
         <ul>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
          <li><a href="#">item1</a> </li>
        </ul>
    </li>
    <li class="last"><a href="#">Welcome Admin</a>
         <ul>
          <li><a href="#">Subitem One</a></li>
          <li><a href="#">Subitem Two</a></li>
          <li><a href="#">Subitem Three</a> </li>
        </ul>      
    </li>
  </ul>
 </div>
</nav>
<body marginheight="0">
</body >
</html>

CSS:
 header{
  height:80px;
  width:100%;
  background: -webkit-linear-gradient(160deg,white, orange); /* For Safari 5.1 to 6.0  */
  background: -o-linear-gradient(180deg,white, orange); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg,white, orange); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg,white, orange); /* Standard syntax (must be last) */   }
#logo{margin-top:13px;}
#menu {
  background:#000;
  width:100%;
  height:40px;
  border-radius: 3px;
  float:left;
}
#menu ul ul {
  display: none;
}
#menu ul li:hover > ul {
  display: block;
}
#menu ul {
  padding: 0px;
  border-radius: 5px;
  list-style: none;
  margin:0;
  position: relative;
  display: block;
}
#menu ul:after {
  content:"";
  clear: both;
  display: block;
}
#menu ul li {
  float: left;
}
#menu ul li:hover {
  color:#fff;
}
#menu ul li:hover a {
  background:#fff;
  color: #000;
}
#menu ul li a {
  display: block;
  padding:0 10px;
  color: #FFF;
  text-decoration: none;
  line-height:40px;
}
#menu ul ul {
  background: #fff;
  padding:0;
  position: absolute;
  top: 40px;
  box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
}
#menu ul ul li {
  float: none;
  position: relative;
}
#menu ul ul li a {
  padding: 15px 40px;
  color: #fff;
  width:150px;
  height:50px;
}
#menu ul ul li a:hover {
  background: #000;
  color:#fff;
}
 #menu ul li.last {
   float:right;
}

在开始正文标记之前有一个关闭的导航标记。请解决这个问题,以便我们知道开始导航标签应该在哪里。