JavaScript之实现单选复选、菜单以及返回顶部实例
1、单选、复选以及反选实例
其实主要是利用for循环提取标签，然后更改checked属性值实现的
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div>
<input type="button" value="全选" onclick="CheckAll();"/>
<input type="button" value="取消" onclick="CancleAll();"/>
<input type="button" value="反选" onclick="Reverse();">
<!--//ondblclick表示双击-->
</div>
<table>
<thead>
<th>序号</th>
<th>用户名</th>
<th>年龄</th>
</thead>
<tbody >
<tr>
<td><input class="c1" type="checkbox"/></td>
<td>jay</td>
<td>23</td>
</tr>
<tr>
<td><input class="c1" type="checkbox"/></td>
<td>Bob</td>
<td>23</td>
</tr>
<tr>
<td><input class="c1" type="checkbox"/></td>
<td>peter</td>
<td>23</td>
</tr>
</tbody>
<script type="text/javascript">
function CheckAll() {
var tb = document.getElementById('tb');
var checks = tb.getElementsByClassName('c1');
for (var i=0;i<checks.length;i++){
var current_check = checks[i];
current_check.checked = true;
// 循环每一个标签
}
}
function CancleAll() {
var tb = document.getElementById('tb');
var checks = tb.getElementsByClassName('c1');
for (var i=0;i<checks.length;i++){
var current_check = checks[i];
current_check.checked = false;
// 循环每一个标签
}
}
function Reverse() {
var tb = document.getElementById('tb');
var checks = tb.getElementsByClassName('c1');
for (var i = 0; i < checks.length; i++) {
var current_check = checks[i];
if (current_check.checked) {
current_check.checked = false;
} else {
current_check.checked = true;
}
}
}
</script>
</table>
</body>
</html>
2、tab菜单实例
利用一种对应关系，实现一个tab菜单，主要思路是绑定每两个选项的关系，即当选中一个，则显示出与之对应的选项框，利用for循环实现显示与否
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>菜单</title>
<style>
ul{
list-style: none;
margin: 0;
padding: 0;
}
ul li{
float: left;
background-color: blue;
color: black;
padding: 10px 12px;
}
.clearfix:after {
display: block;
content: '.';
height: 0;
visibility: hidden;
clear: both;
}
.tab-menu .title{
background-color: bisque;
}
.tab-menu .content{
border: 1px solid black;
min-height: 150px;
}
.hide{
display: none;
}
.tab-menu .title .active{
background-color: white;
color:red ;
}
/*选中时候的状态*/
</style>
</head>
<body>
<div style=" 400px;margin: 0 auto">
<div class="tab-menu">
<div class="title clearfix">
<ul>
<li target='h1' class="active" onclick="Show(this);">价格趋势</li>
<li target='h3' onclick="Show(this);">市场分布</li>
<li target='h2' onclick="Show(this);">其他</li>
</ul>
</div>
<div >
<div con="h1">contnet1</div>
<div con="h2" class="hide">contnet2</div>
<div con="h3" class="hide">contnet3</div>
</div>
</div>
</div>
<script>
function Show(ths) {
//args表示当前标签
var target=ths.getAttribute('target');
//给自己添加样式active，兄弟标签则去掉
ths.className='active';
var brothers = ths.parentElement.children;
for (var i=0;i<brothers.length;i++){
if(ths == brothers[i]){
}else{brothers[i].removeAttribute('class')}
}
var contents = document.getElementById('jay').children;
for(var j=0;j<contents.length;j++){
var current_content =contents[j];
var con = current_content.getAttribute('con')
if(con == target){
current_content.classList.remove('hide')
}else{current_content.className='hide'}
}
}
</script>
</body>
</html>
执行结果如图所示，点击则会切换
3、往页面列表里面自动添加输入的文本内容
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div >
<input type="text">
<input type="button" value="添加" onclick="foo(this)">
</div>
<div>
<ul >
<li>jay</li>
<li>BOb</li>
</ul>
</div>
<script>
function foo(ths) {
var val = ths.previousElementSibling.value;
console.log(val);
var ret = document.getElementById('commentList');
var str = "<li>" + val + "</li>";
ret.insertAdjacentHTML('beforeEnd', str);//该方法只能添加字符串
ths.previousElementSibling.value = '';
// 第二种方法
var tag = document.createElement('li');
tag.innerText = val;
ret.appendChild(tag);
}
</script>
</body>
</html>
执行结果如
图
可以往下面随便添加内容
insertAdjacentHTML第一个参数有多种用法，如图
3、克隆移动标签
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h2 >333</h2>
<div >
<div class="item">1</div>
<div class="item">1</div>
</div>
<script>
var h =document.getElementById('h1');
var c=document.getElementById('container');
var newH = h.cloneNode(true);//没有true参数的话，不会克隆标签里面的东西
c.appendChild(newH)
</script>
</body>
</html>
执行结果如图
4、返回顶部
scrollTop表示的是离顶部的距离，可以调节这个属性的数值，随时返回顶部，代码如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.go_top{
position: fixed;
right:27px;
bottom: 40px;
50px;
height: 40px;
background-color: black;
color: white;
}
.hide{
display: none;
}
</style>
</head>
<body onscroll="Func()">
<!--只要触动滚轮，就触动发该函数-->
<div >
<h1>你好</h1>
</div>
<div >
<a href="javascript:void (0)" onclick="goTop();">返回顶部</a>
<!--href="javascript:void (0)表示什么也不干-->
</div>
<script>
function goTop() {
document.body.scrollTop=0
}
// 返回顶部
function Func() {
console.log(123);
var scrollTop=document.body.scrollTop;
var li=document.getElementById('i2');
if(scrollTop>150){
li.classList.remove('hide')
}else{
li.classList.add('hide')
}
}
//距离大于50px才触发函数，让这个返回顶部的框框显示出来
</script>
</body>
</html>
5计时器执行函数
如图，主要是setInterval方法的使用