本篇文章通过代码实例来给大家介绍一下javascript实现焦点图轮播效果。有一定的参考价值，有需要的朋友可以参考一下，希望对大家有所帮助。

JS实现焦点图轮播效果

效果图：

(不过里面的图片路径需要自己改成自己的图片路径，否则是没有图片显示的哦)

代码如下，复制即可使用：

JS实现焦点图轮播效果

* {

margin: 0;

padding: 0;

text-decoration: none;

}

body {

padding: 20px;

}

#container {

width: 600px;

height: 400px;

border: 3px solid #333;

overflow: hidden;

position: relative;

}

#list {

width: 4200px;

height: 400px;

position: absolute;

z-index: 1;

}

#list img {

float: left;

}

#buttons {

position: absolute;

height: 10px;

width: 100px;

z-index: 2;

bottom: 20px;

left: 250px;

}

#buttons span {

cursor: pointer;

float: left;

border: 1px solid #fff;

width: 10px;

height: 10px;

border-radius: 50%;

background: #333;

margin-right: 5px;

}

#buttons .on {

background: orangered;

}

.arrow {

cursor: pointer;

display: none;

line-height: 39px;

text-align: center;

font-size: 36px;

font-weight: bold;

width: 40px;

height: 40px;

position: absolute;

z-index: 2;

top: 180px;

background-color: RGBA(0, 0, 0, .3);

color: #fff;

}

.arrow:hover {

background-color: RGBA(0, 0, 0, .7);

}

#container:hover .arrow {

display: block;

}

#prev {

left: 20px;

}

#next {

right: 20px;

}

window.onload = function() {

var container = document.getElementById('container');

var list = document.getElementById('list');

var buttons = document.getElementById('buttons').getElementsByTagName('span');

var prev = document.getElementById('prev');

var next = document.getElementById('next');

var index = 1;

var len = 5;

var animated = false;

var interval = 3000;

var timer;

function animate(offset) {

if(offset == 0) {

return;

}

animated = true;

var time = 300;

var inteval = 10;

var speed = offset / (time / inteval);

var left = parseInt(list.style.left) + offset;

var go = function() {

if((speed > 0 && parseInt(list.style.left) < left) ||

(speed < 0 && parseInt(list.style.left) > left)) {

list.style.left = parseInt(list.style.left) + speed + 'px';

setTimeout(go, inteval);

} else {

list.style.left = left + 'px';

if(left > -200) {

list.style.left = -600 * len + 'px';

}

if(left < (-600 * len)) {

list.style.left = '-600px';

}

animated = false;

}

}

go();

}

function showButton() {

for(var i = 0; i < buttons.length; i++) {

if(buttons[i].className == 'on') {

buttons[i].className = '';

break;

}

}

buttons[index - 1].className = 'on';

}

function play() {

timer = setTimeout(function() {

next.onclick();

play();

}, interval);

}

function stop() {

clearTimeout(timer);

}

next.onclick = function() {

if(animated) {

return;

}

if(index == 5) {

index = 1;

} else {

index += 1;

}

animate(-600);

showButton();

}

prev.onclick = function() {

if(animated) {

return;

}

if(index == 1) {

index = 5;

} else {

index -= 1;

}

animate(600);

showButton();

}

for(var i = 0; i < buttons.length; i++) {

buttons[i].onclick = function() {

if(animated) {

return;

}

if(this.className == 'on') {

return;

}

var myIndex = parseInt(this.getAttribute('index'));

var offset = -600 * (myIndex - index);

animate(offset);

index = myIndex;

showButton();

}

}

container.onmouseover = stop;

container.onmouseout = play;

play();

}

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