小白之js原生轮播图
html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="banner.css">
<script src="banner.js"></script>
</head>
<body>
<div class="ban">
<ul id="scroll">
<li>
<a href="#">
<img src="1.jpg" style="height:282px;376px;" alt="">
</a>
</li>
<li>
<a href="#">
<img src="2.jpg" style="height:282px;376px;" alt="">
</a>
</li>
<li>
<a href="#">
<img src="3.jpg" style="height:282px;376px;" alt="">
</a>
</li>
</ul>
<ul id="btns">
<span class="active"></span>
<span></span>
<span></span>
</ul>
<button id="shang"><</button>
<button id="xia">></button>
</div>
</body>
</html>
css：(banner.css)
.ban{position:relative;height:282px;376px;}
#scroll{list-style: none;margin:0;padding:0;}
#scroll>li{display: none}
#btns{376px;position:absolute;bottom:0;text-align: center;padding:5px 0;}
#btns span{background:#f5f5f5;display: inline-block;10px;height:10px;border-radius: 50%;}
.ban .active{background:#555!important;}
#shang,#xia{background: rgba(255,255,255,0.7);padding:10px;border: 0;position: absolute;top:130px;z-index: 100000;color:#000;font-weight: bold}
#shang{left:0}
#xia{right:0}
js：(banner.js)
var scroll = document.getElementById("scroll");
var scrollli = document.getElementById("scroll").getElementsByTagName("li");
var btns = document.getElementById("btns").getElementsByTagName("span");
var shangbtn = document.getElementById("shang");
var xiabtn = document.getElementById("xia");
var index = 1;
scrollli[0].style.display = "block";
function clearimg(){
/*把所有图片隐藏*/
for(var i=0;i<scrollli.length;i++){
scrollli[i].style.display="none";
}
}
function clearactive(){
for(var i=0;i<btns.length;i++){
btns[i].classList.remove("active");
}
}
xiabtn.onclick=function() {
clearimg();clearactive();
index++;
if(index>3){
index=1;
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
};
shangbtn.onclick=function() {
clearimg();clearactive();
index--;
if(index<1){
index=3
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
};
function btnsclick(y) {
clearimg();
clearactive();
console.log(y);
/*把需要显示的图片显示出来*/
console.log(scrollli[0])
scrollli[y].style.display = "block";
btns[y].classList.add("active");
index = y+1;
}
for(var i=0; i<btns.length; i++){
(function(j){
btns[j].onclick = function () {
btnsclick(j)
};
})(i)
}
setInterval(function () {
clearimg();
clearactive();
index++;
if(index>3){
index=1;
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
},3000);
单文件：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.ban{position:relative;height:282px;376px;}
#scroll{list-style: none;margin:0;padding:0;}
#scroll>li{display: none}
#btns{376px;position:absolute;bottom:0;text-align: center;padding:5px 0;}
#btns span{background:#f5f5f5;display: inline-block;10px;height:10px;border-radius: 50%;}
.ban .active{background:#555!important;}
#shang,#xia{background: rgba(255,255,255,0.7);padding:10px;border: 0;position: absolute;top:130px;z-index: 100000;color:#000;font-weight: bold}
#shang{left:0}
#xia{right:0}
</style>
</head>
<body>
<div class="ban">
<ul id="scroll">
<li>
<a href="#">
<img src="1.jpg" style="height:282px;376px;" alt="">
</a>
</li>
<li>
<a href="#">
<img src="2.jpg" style="height:282px;376px;" alt="">
</a>
</li>
<li>
<a href="#">
<img src="3.jpg" style="height:282px;376px;" alt="">
</a>
</li>
</ul>
<ul id="btns">
<span class="active"></span>
<span></span>
<span></span>
</ul>
<button id="shang"><</button>
<button id="xia">></button>
</div>
<script>
var scroll = document.getElementById("scroll");
var scrollli = document.getElementById("scroll").getElementsByTagName("li");
var btns = document.getElementById("btns").getElementsByTagName("span");
var shangbtn = document.getElementById("shang");
var xiabtn = document.getElementById("xia");
var index = 1;
scrollli[0].style.display = "block";
function clearimg(){
/*把所有图片隐藏*/
for(var i=0;i<scrollli.length;i++){
scrollli[i].style.display="none";
}
}
function clearactive(){
for(var i=0;i<btns.length;i++){
btns[i].classList.remove("active");
}
}
xiabtn.onclick=function() {
clearimg();clearactive();
index++;
if(index>3){
index=1;
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
};
shangbtn.onclick=function() {
clearimg();clearactive();
index--;
if(index<1){
index=3
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
};
function btnsclick(y) {
clearimg();
clearactive();
console.log(y);
/*把需要显示的图片显示出来*/
console.log(scrollli[0])
scrollli[y].style.display = "block";
btns[y].classList.add("active");
index = y+1;
}
for(var i=0; i<btns.length; i++){
(function(j){
btns[j].onclick = function () {
btnsclick(j)
};
})(i)
}
setInterval(function () {
clearimg();
clearactive();
index++;
if(index>3){
index=1;
}
/*把需要显示的图片显示出来*/
scrollli[index-1].style.display="block";
btns[index-1].classList.add("active");
},3000);
</script>
</body>
</html>