1.背景介绍
在js-task-6中，我们需要实现一个侧边栏高亮的功能，今天就来讲一下如何实现。
2.知识剖析
实现侧边栏高亮，网页刷新后仍然保持高亮状态，就需要我们存储其高亮状态的数据。
3.常见问题
如何存储高亮状态？
4.解决方案
这里使用了localStorage存储其状态
5.编码实战
<!DOCTYPE html>
<html lang="zh-cmn-Hans">
<head>
<meta charset="utf-8">
<meta name="format-detection" content="telephone=no">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
<meta name="viewport" content="width=device-width,initial-scale=1,user-scalable=no">
<title>侧边栏高亮</title>
<style>
html, body, ul, li, div {
margin: 0;
padding: 0;
}
::-webkit-scrollbar {
width: 0;
}
li {
list-style: none;
}
aside {
position: fixed;
top: 0;
bottom: 0;
left: 0;
overflow: auto;
background-color: #ccc;
width: 300px;
text-align: center;
}
.toggle {
padding-bottom: .5em;
}
.title {
font-size: 20px;
line-height: 1.5;
color: #0d99a5;
cursor: pointer;
}
.title:hover {
background-color: red !important;
}
ul.body {
display: none;
}
.list {
font-size: 16px;
color: #0000f1;
}
.list:hover {
background-color: #00ee00 !important;
cursor: pointer;
}
</style>
</head>
<body>
<aside>
<div class="toggle">
<div class="title" index="1">title01</div>
<ul class="body" index="1">
<li class="list" index="1">list01</li>
<li class="list" index="2">list02</li>
<li class="list" index="3">list03</li>
<li class="list" index="4">list04</li>
</ul>
</div>
<div class="toggle">
<div class="title" index="2">title02</div>
<ul class="body" index="2">
<li class="list" index="1">list01</li>
<li class="list" index="2">list02</li>
<li class="list" index="3">list03</li>
<li class="list" index="4">list04</li>
</ul>
</div>
<div class="toggle">
<div class="title" index="3">title03</div>
<ul class="body" index="3">
<li class="list" index="1">list01</li>
<li class="list" index="2">list02</li>
<li class="list" index="3">list03</li>
<li class="list" index="4">list04</li>
</ul>
</div>
<div class="toggle">
<div class="title" index="4">title04</div>
<ul class="body" index="4">
<li class="list" index="1">list01</li>
<li class="list" index="2">list02</li>
<li class="list" index="3">list03</li>
<li class="list" index="4">list04</li>
</ul>
</div>
<div class="toggle">
<div class="title" index="5">title05</div>
<ul class="body" index="5">
<li class="list" index="1">list01</li>
<li class="list" index="2">list02</li>
<li class="list" index="3">list03</li>
<li class="list" index="4">list04</li>
</ul>
</div>
</aside>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
<script>
$(function () {
//取值title
if (localStorage.getItem('title')) {
for (var i = 0; i < JSON.parse(localStorage.getItem('title')).length; i++) {
if (JSON.parse(localStorage.getItem('title'))[i] == 1) {
$(".title[index=" + i + "]").css("background-color", "red");
$(".title[index=" + i + "]+ul").css("display", "block");
} else {
$(".title[index=" + i + "]").css("background-color", "transparent");
$(".title[index=" + i + "]+ul").css("display", "none");
}
}
}
//取list数组
if (localStorage.getItem('list')) {
for (var i = 0; i < JSON.parse(localStorage.getItem('list')).length; i++) {
for (var j = 0; j < JSON.parse(localStorage.getItem('list'))[i].length; j++) {
if (JSON.parse(localStorage.getItem('list'))[i][j] == 1) {
$(".title[index=" + i + "]").siblings("ul.body").children(".list[index=" + j + "]").css("background-color", "#00ee00");
} else {
$(".title[index=" + i + "]").siblings('ul.body').children(".list[index=" + j + "]").css("background-color", "transparent");
}
}
}
}
//存数组title
$('.title').click(function () {
var title = [];
$(".title").css('background-color', 'transparent');
$("ul.body").css("display", "none");
$(this).css('background-color', 'red');
$(this).siblings('ul.body').toggle();
if ($(this).siblings('ul.body').css('display') === 'block') {
title[Number($(this).attr("index"))] = 1;
console.log(title[Number($(this).attr("index"))]);
localStorage.setItem('title', JSON.stringify(title));
} else if ($(this).siblings('ul.body').css('display') === 'none') {
title[Number($(this).attr("index"))] = 0;
localStorage.setItem('title', JSON.stringify(title));
}
console.log($(this).siblings('ul.body').css("display"));
}
)
//存数组list
$('.list').click(function () {
//定义二维数组
var list = new Array(6);
for (var i = 0; i < 6; i++) {
list[i] = new Array(5);
}
//重置.list的背景色
$(".list").css('background-color', 'transparent');
$(this).css('background-color', '#00ee00');
//用Number转化index的字符串值
list[Number($(this).parent().attr("index"))][Number($(this).attr("index"))] = 1;
//存数组需先把数组转化为JSON
localStorage.setItem('list', JSON.stringify(list));
}
)
});
</script>
</body>
</html>
6.扩展思考
还有什么方法存储高亮状态？
可以使用$stateParames，在url中存取状态。
7.参考文献
8.更多讨论
如何创建二位数组？
先建立一维数组，再将数组的每一项都设置为二维数组:
var x=5,y=6;//数组的长度
var a=new Array(x);
for(var i=0;i< x ;i++){
a[i]=new Array(y);
}
console.log(a);
