我在做到5.2步骤的时候按按钮没有反应，视频里面 有反应 main.className += ' main-i_active';感觉这里有问题，求救
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style type="text/css">
* {
padding: 0;
margin: 0;
list-style-type: none;
text-decoration: none;
border: 0;
}
body {
background-color: #fff;
color: #555;
font-family: 'Avenir Next';
font-size: 14px;
-webkit-font-smoothing: antialiased; /*字体平滑*/
}
.slider .main .main-i, .slider .main, .slider {
width: 100%;
height: 400px;
position: relative;
}
/*幻灯片区域*/
.slider .main {
overflow: hidden;
}
/*每一个幻灯片样式*/
.slider .main .main-i {
}
.slider .main .main-i img {
width: 100%;
position: absolute;
left: 0;
top: 0;
z-index: 1;
}
.slider .main .main-i .caption {
position: absolute;
right: 50%;
top: 30%;
z-index: 9;
}
.slider .main .main-i .caption h2 {
font-size: 40px;
line-height: 50px;
color: #B5b5b5;
text-align: right;
}
.slider .main .main-i .caption h3 {
font-size: 40px;
font-size: 70px;
line-height: 70px;
color: #000000;
text-align: right;
}
/*控制按钮区域*/
.slider .ctrl {
width: 100%;
height: 13px;
line-height: 13px;
text-align: center;
position: absolute;
left: 0;
bottom: -13px;
}
.slider .ctrl .ctrl-i {
display: inline-block; /*一行内块级元素*/
width: 150px;
height: 13px;
background-color: #666;
box-shadow: 0 1px 1px rgba(0,0,0,.3);
position: relative;
z-index: 1;
margin-left: 1px;
}
.slider .ctrl .ctrl-i img {
width: 100%;
position: absolute;
left: 0;
bottom: 50px;
z-index: 1;
opacity: 0;
-webkit-transition: all .2s; /*渐变特效*/
}
/*hover 到控制按钮的样式*/
.slider .ctrl .ctrl-i:hover {
background-color: #F0F0F0;
}
.slider .ctrl .ctrl-i:hover img {
bottom: 13px;
opacity: 1;
}
/*active 当前展示的状态*/
.slider .ctrl .ctrl-i_active:hover,
.slider .ctrl .ctrl-i_active {
background-color: #000;
}
.slider .ctrl .ctrl-i_active:hover img {
opacity: 0;
}
/*幻灯片切换样式*/
.slider .main .main-i {
opacity: 0;
position: absolute;
top: 0;
right: 50%;
-webkit-transition: all .5s;
}
.slider .main .main-i h2 {
margin-right: 45px;
}
.slider .main .main-i h3 {
margin-right: -45px;
}
.slider .main .main-i h2,
.slider .main .main-i h3 {
-webkit-transition: all .8s 1s;
}
.slider .main .main-i_active {
right: 0;
opacity: 1;
}
.slider .main .main-i_active h2,
.slider .main .main-i_active h3 {
margin-right: 0;
}
</style>
</head>
<body>
<div class="slider">
<!-- 0. 修改 VIEW Template （关键字替换）增加 template id-->
<div class="main" id="template_main">
<div class="main-i" id="main_{{index}}">
<div class="caption">
<h2>{{h2}}</h2>
<h3>{{h3}}</h3>
</div>
<img src="img/{{index}}.jpg" />
</div>
</div>
<div class="ctrl" id="template_ctrl">
<a class="ctrl-i" id="ctrl_{{index}}" href="javascript:switchSlider({{index}};);">
<img src="img/{{index}}.jpg" /></a>
</div>
</div>
</body>
<script type="text/javascript">
// 1.数据定义(实际生产环境中，应用后台数据)
var data = [
{ img: 1, h2: 'h1', h3: 'h2' },
{ img: 2, h2: 'h1', h3: 'h2' },
{ img: 3, h2: 'h1', h3: 'h2' },
{ img: 4, h2: 'h1', h3: 'h2' },
{ img: 5, h2: 'h1', h3: 'h2' },
{ img: 6, h2: 'h1', h3: 'h2' },
{ img: 7, h2: 'h1', h3: 'h2' }
];
//2.通用函数
var g = function (id) {
if (id.substr(0, 1) == '.') { return document.getElementsByClassName(id.substr(1)); }
return document.getElementById(id);
}
//添加幻灯片的操作（所有幻灯片和按钮）
function addSliders() {
//3.1 获取模板
var tpl_main = g('template_main').innerHTML
.replace(/^\s*/, '')//去掉头部空白符
.replace(/\s*$/, '');//去掉尾部空白符
var tpl_ctrl = g('template_ctrl').innerHTML
.replace(/^\s*/, '')//去掉头部空白符
.replace(/\s*$/, '');//去掉尾部空白符
//3.2 定义最终输出 HTML 变量
var out_main = [];
var out_ctrl = [];
//3.3 遍历所有数据，构建最终输出的 HTML
for (i in data) {
var _html_main = tpl_main
.replace(/{{index}}/g, data[i].img)
.replace(/{{h2}}/g, data[i].h2)
.replace(/{{h3}}/g, data[i].h3);//运用数组，调用内容
var _html_ctrl = tpl_ctrl
.replace(/{{index}}/g, data[i].img);
out_main.push(_html_main);
out_ctrl.push(_html_ctrl);
}
//3.4 把html 回写到对应的DOM 里面
g('template_main').innerHTML = out_main.join('');
g('template_ctrl').innerHTML = out_ctrl.join('');
}
// 5. 幻灯片切换
function switchSlider(n) {
// 5.1 获得要展现的幻灯片和控制按钮 DOM
var main = g('main_' + n);
var ctrl = g('ctrl_' + n);
// 5.2 获得所有的幻灯片以及控制按钮
var clear_main = g('.main-i');
var clear_ctrl = g('.ctrl-i');
main.className += ' main-i_active';
ctrl.className += ' ctrl-i_active';
}
// 4. 定义合适处理幻灯片输出
//window执行完毕
window.onload = function () {
addSliders();
}
</script>
</html>
