Javascript:旋转木马活动点和左右按钮

Question

我是初级javascript开发人员。我决定使用纯Javascript制作旋转木马。我成功地滑动了转盘。我已经决定制作活动点(也可以点击(，我希望点的背景颜色在滑动和左右按钮时发生变化。我已经创建了点，但我不知道如何在我的幻灯片功能以及左右按钮中实现点。这是我的代码：

Also please explain me the logic. Thank you

const images = document.getElementById('imgs');
const allImages = document.querySelectorAll('#imgs img');
const leftBtn = document.getElementById('left');
const rightBtn = document.getElementById('right');
let index = 0;
function run() {
const dot = [...document.getElementsByClassName('star')];
index++;

if (index > allImages.length - 1) {
index = 0
dot.forEach(i => i.classList.add('active'))
}
imgs.style.transform = `translateX(${-index * 500}px)`
}
const dot = allImages.forEach(i => {
const elem = document.createElement('div');
elem.classList.add('star');
document.body.appendChild(elem)
})
let x = setInterval(run, 2000);
images.onmouseover = () => {
clearInterval(x)
}
images.onmouseout = () => {
x = setInterval(run, 2000);
}

*{
box-sizing: border-box;
}
body {
margin: 0;
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
}
.carousel {
overflow: hidden;
width: 500px;
height: 500px;
box-shadow: 2px 2px 5px rgba(0, 0, 0, .3);
border-radius: 5px;
}
.image-container {
display: flex;
transition: transform 300ms linear;
transform: translateX(0);
}
img {
width:500px;
height: 500px;
object-fit: cover;
}
.star{
cursor: pointer;
height: 15px;
width: 15px;
margin: 0 10px;
border-radius: 50%;
display: inline-block;
transition: background-color 0.6s ease;
background-color: #eeeeee;
}
.star.active{
background-color: red;
}
button{
cursor: pointer;
position: relative;
font-size: 18px;
transition: 0.6s ease;
user-select: none;
height: 50px;
width: 40px;
display: flex;
justify-content: center;
align-items: center;
align-content: center;
top: calc(50% - 25px);
}
button:hover {
background-color: rgba(0,0,0,0.8);
};
button.left {
border-radius: 3px 0 0 3px;
right: 0;
}
button.left {
border-radius: 3px 0 0 3px;
left: 0;
}

<button id="left">&#10094;</button>
<button id="right">&#10095;</button>
<div class="carousel">
<div class="image-container" id="imgs" >
<img src="https://images.unsplash.com/photo-1599736375341-51b0a848f3c7?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60" alt="">
<img src="https://images.unsplash.com/photo-1516026672322-bc52d61a55d5?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60" alt="">
<img src="https://images.unsplash.com/photo-1573081586928-127ecc7948b0?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60" alt="">
<img src="https://images.unsplash.com/flagged/photo-1572850005109-f4ac7529bf9f?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60" alt="">
</div>
</div>

Answer 1

您已接近结果。在run函数中，只需更改当前活动dot的类，并将新的类设置为活动。为了便于理解，我将您的dot变量重命名为dots。

function run() {
const dots = [...document.getElementsByClassName('star')];
index++;

if (index > allImages.length - 1) {
index = 0
}

dots.forEach((dot, i) => {
if (dot.classList.contains('active')) dot.classList.remove('active');
if (i === index) dot.classList.add('active'));
}
imgs.style.transform = `translateX(${-index * 500}px)`
}