麻烦老师看一下，报错原因：
轮播.html:136 Uncaught TypeError: Cannot set property 'onmouseover' of null
at slideImg (轮播.html:136)
at 轮播.html:153
slideImg @ 轮播.html:136 (anonymous) @ 轮播.html:153
找了一下没有找到解决办法。
html>
综合实例*{
margin:0;
padding:0;
}
ul{
list-style: none;
}
body{
font-family:"微软雅黑";
color:#14191e;
}
.main{
width:1200px;
height:460px;
margin:30px auto;
overflow:hidden;
position:relative;
}
.banner{
width:1200px;
height:460px;
overflow:hidden;
position:relative;
}
.banner-slide{
width:1200px;
height:460px;
background-repeat: no-repeat;
position:absolute;
display:none;
}
.slide1{
background-image:url("C:/huaXiaXia/Sublime%20Text%203/教辅/实现轮播教辅/JavaScript实现轮播特效(代码)/img/bg1.jpg");
}
.slide2{
background-image:url("C:/huaXiaXia/Sublime%20Text%203/教辅/实现轮播教辅/JavaScript实现轮播特效(代码)/img/bg2.jpg");
}
.slide3{
background-image:url("C:/huaXiaXia/Sublime%20Text%203/教辅/实现轮播教辅/JavaScript实现轮播特效(代码)/img/bg3.jpg");
}
.slide-active{
display:block;
}
.button{
position:absolute;
width:40px;
height:80px;
left:244px;
top:50%;
margin-top:-40px;
background-color:green;
background: url("C:/huaXiaXia/Sublime%20Text%203/教辅/实现轮播教辅/JavaScript实现轮播特效(代码)/img/arrow.png") no-repeat center center;
}
.pre{
transform:rotate(180deg);
}
.next{
left:auto;
right:0;
}
.button:hover{
background-color:#333;
opacity:0.5;
filter:alpha(opacity:50);
}
.dots{
position:absolute;
right:20px;
bottom:24px;
text-align:right;
}
.dots span{
display:inline-block;
width:12px;
height:12px;
border-radius:50%;
/*rbga,a为透明度*/
background:rgba(7,17,27,0.4);
/*阴影，水平 垂直 距离 模糊程度 颜色 内阴影*/
box-shadow: 0 0 0 2px rgba(255,255,255,0.8) inset;
margin-left:8px;
line-height:12px;
cursor:pointer;
}
.dots span.active{
box-shadow: 0 0 0 2px rgba(7,17,27,0.4) inset;
background:#fff;
}
//封装一个getElementById()的方法
function byId(id){
return typeof(id) === "string"?document.getElementById(id):id;
}
var index=0,
timer=null,
pics=byId("banner").getElementsByTagName("div"),
len=pics.length;
function slideImg(){
var main=byId("main");
main.onmouseover = function(){
//滑过清除定时器
}
main.onmouseout = function(){
//setTimeout超时定时器 setInterval界限调用
timer=setInterval(function(){
index++;
if(index>=len){
index = 0;
}
//切换图片
// changeImg();
console.log(index);
},2000);
}
}
slideImg();
//切换图片
// function changeImg(){
// //遍历banner下的所有div将其隐藏
// for(var i=0;i
// pics[i].style.display="none";
// }
// //根据index所有找到div将其显示出来
// pics[index].style.display='block';
// }
