如何使用 HTML、JS 和 CSS 自动执行图像轮播？

Question

我不是很擅长JS，所以我不得不通过视频解释如何使用HTML、CSS和JS制作图像轮播。 我希望能够使它自动化，但由于我缺乏经验，不知道该怎么做。 如果有人可以解释如何修改此代码以能够通过箭头进行手动输入并自动循环到下一张图像，我将不胜感激。

这是手动按钮 slider 的代码（HTML、JS、CSS）

    <section aria-label = 'sliderImages'>
        <div class = 'slider' data-slider>
            <button class = 'backButton' data-slider-button = 'previous'></button>
            <button class = 'nextButton' data-slider-button = 'next'></button>
            <ul data-slides>
                <li class = 'slide' data-active>
                <img src = '/Images/Red.png' alt = ''>
                </li>
                <li class = 'slide'>
                <img src = '/Images/Yellow.png' alt = ''>
                </li>
                <li class = 'slide'>
                <img src = '/Images/Blue.png' alt = ''>
                </li>
                <li class = 'slide'>
                <img src = '/Images/Green.png' alt = ''>
                </li>
            </ul>
        </div>
    </section>

const buttons = document.querySelectorAll('[data-slider-button]')

buttons.forEach(button => {
    button.addEventListener('click', () => {
        const offset = button.dataset.sliderButton === 'next' ? 1 : -1
        const slides = button
        .closest('[data-slider]')
        .querySelector('[data-slides]')

    const activeSlide = slides.querySelector('[data-active]')
    let newIndex = [...slides.children].indexOf(activeSlide) + offset
    if  (newIndex < 0) newIndex = slides.children.length - 1
    if (newIndex >= slides.children.length) newIndex = 0

    slides.children[newIndex].dataset.active = true
    delete activeSlide.dataset.active
    })
})

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}


.slides {
    width: 100%;
    height: 100vh;
    position: relative;
}

.slide {
    position: absolute;
    inset: 0;
    opacity: 0;
    transition: 0.8s opacity ease-in;
    transition-delay: 0.8s;

}

.slide[data-active] {
    opacity: 1;
    transition-delay: 0s;
    z-index: 1;
}

.slide > img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
}

.backButton {
    position: absolute;
    width: 24px;
    height: 45px;
    top: 50%;
    left: 50px;
    transform: translate(0%, 50%);
    border: none;
    background: url('/Images/Left Arrow.png');
    z-index: 2;
}

.backButton:hover {
    cursor: pointer;
}

.nextButton {
    position: absolute;
    width: 24px;
    height: 45px;
    top: 50%;
    right: 50px;
    transform: translate(0%, 50%);
    border: none;
    background: url('/Images/Right Arrow.png');
    z-index: 2;
}

.nextButton:hover {
    cursor: pointer;
}

Answer 1

您可以使用以下代码制作自动图像 slider。或者更改您的 js 代码并设置 setTimeout() function。

 let slideIndex = 0; showSlides(); function showSlides() { let i; let slides = document.getElementsByClassName("mySlides"); let dots = document.getElementsByClassName("dot"); for (i = 0; i < slides.length; i++) { slides[i].style.display = "none"; } slideIndex++; if (slideIndex > slides.length) {slideIndex = 1} for (i = 0; i < dots.length; i++) { dots[i].className = dots[i].className.replace(" active", ""); } slides[slideIndex-1].style.display = "block"; dots[slideIndex-1].className += " active"; setTimeout(showSlides, 2000); // Change image every 2 seconds }

 * {box-sizing: border-box;}.mySlides {display: none;} img {vertical-align: middle;} /* Slideshow container */.slideshow-container { max-width: 1000px; position: relative; margin: auto; } /* Caption text */.text { color: #f2f2f2; font-size: 15px; padding: 8px 12px; position: absolute; bottom: 8px; width: 100%; text-align: center; } /* Number text (1/3 etc) */.numbertext { color: #f2f2f2; font-size: 12px; padding: 8px 12px; position: absolute; top: 0; } /* The dots/bullets/indicators */.dot { height: 15px; width: 15px; margin: 0 2px; background-color: #bbb; border-radius: 50%; display: inline-block; transition: background-color 0.6s ease; }.active { background-color: #717171; } /* Fading animation */.fade { animation-name: fade; animation-duration: 1.5s; } @keyframes fade { from {opacity: .4} to {opacity: 1} } /* On smaller screens, decrease text size */ @media only screen and (max-width: 300px) {.text {font-size: 11px} }

 <h2>Automatic Slideshow</h2> <p>Change image every 2 seconds:</p> <div class="slideshow-container"> <div class="mySlides fade"> <div class="numbertext">1 / 3</div> <img src="https://www.w3schools.com/howto/img_nature_wide.jpg" style="width:100%"> <div class="text">Caption Text</div> </div> <div class="mySlides fade"> <div class="numbertext">2 / 3</div> <img src="https://www.w3schools.com/howto/img_snow_wide.jpg" style="width:100%"> <div class="text">Caption Two</div> </div> <div class="mySlides fade"> <div class="numbertext">3 / 3</div> <img src="https://www.w3schools.com/howto/img_mountains_wide.jpg" style="width:100%"> <div class="text">Caption Three</div> </div> </div> <br> <div style="text-align:center"> <span class="dot"></span> <span class="dot"></span> <span class="dot"></span> </div>