.clearfix::after {
display: block
content: ""
clear: both
}
ul,
li {
list-style: none
}
.nav>li {
float: left
margin: 0 10px
}
.nav>li ul {
display: none
}
</style>
</head>
<body>
<ul class="nav clearfix">
<li>
<a href="">微博</a>
<ul>
<li>私信</li>
<li>评论</li>
<li>@我</li>
</ul>
</li>
<li>
<a href="">微博</a>
<ul>
<li>私信</li>
<li>评论</li>
<li>@我</li>
</ul>
</li>
<li>
<a href="">微博</a>
<ul>
<li>私信</li>
<li>评论</li>
<li>@我</li>
</ul>
</li>
<li>
<a href="">微博</a>
<ul>
<li>私信</li>
<li>评论</li>
<li>@我</li>
</ul>
</li>
</ul>
<script>
//案例分析：导航栏里面的li都要有鼠标经过效果 所以需要循环注册鼠标事件
//核心原理：当鼠标经过li里面的第二个孩子ul显示 当鼠标离开 ul隐藏
var nav = document.querySelector('.nav')
var lis = nav.children
for (var i = 0 i < lis.length i++) {
lis[i].onmouseover = function() {
this.children[1].style.display = 'block'
}
lis[i].onmouseout = function() {
this.children[1].style.display = 'none'
}
}
</script>
本文实例讲述了js使用DOM设置单选按钮、复选框及下拉菜单的方法。分享给大家供大家参考。具体实现方法如下：1.设置单选按钮
单选按钮在表单中即<input
type="radio"
/>它是一组供用户选择的对象，但每次只能选一个。每一个都有checked属性，当一项选择为ture时，其它的都变为false.
先贴上一个例子：
复制代码
代码如下:<script
type="text/javascript">
function
getChoice()
{
var
oForm
=
document.forms["uForm1"]
var
aChoices
=
oForm.camera
for
(i
=
0
i
<
aChoices.length
i++)
//遍历整个单选项表
if
(aChoices[i].checked)
//如果发现了被选中项则退出
break
alert("相机品牌是："
+
aChoices[i].value)
}
function
setChoice(iNum)
{
var
oForm
=
document.forms["uForm1"]
oForm.camera[iNum].checked
=
true
}
</script>
<form
method="post"
name="uForm1"
action="addInfo.aspx">
相机品牌：
<p>
<input
type="radio"
name="camera"
id="canon"
value="Canon">
<label
for="canon">Canon</label>
</p>
<p>
<input
type="radio"
name="camera"
id="nikon"
value="Nikon">
<label
for="nikon">Nikon</label>
</p>
<p>
<input
type="radio"
name="camera"
id="sony"
value="Sony"
checked>
<label
for="sony">Sony</label>
</p>
<p>
<input
type="radio"
name="camera"
id="olympus"
value="Olympus">
<label
for="olympus">Olympus</label>
</p>
<p>
<input
type="radio"
name="camera"
id="samsung"
value="Samsung">
<label
for="samsung">Samsung</label>
</p>
<p>
<input
type="radio"
name="camera"
id="pentax"
value="Pentax">
<label
for="pentax">Pentax</label>
</p>
<p>
<input
type="radio"
name="camera"
id="others"
value="其它">
<label
for="others">others</label>
</p>
<p>
<input
type="submit"
name="btnSubmit"
id="btnSubmit"
value="Submit"
class="btn">
</p>
<p>
<input
type="button"
value="检测选中对象"
onclick="getChoice()">
<input
type="button"
value="设置为Canon"
onclick="setChoice(0)">
</p>
</form>
