Why is the opacity not changing for images in this slideshow? (CSS, Javascipt)

Question

I am attempting to build an image carousel. However, I am running into an unexpected behavior with the opacity animation/transition.

I have an .active class that is successfully transitioning between the three img . This .active class adds opacity: 1; . However, as the last img loads into the DOM, it retains its initial opacity: 0; , and even though the .active class is added to each img every six seconds, the opacity doesn't change.

I imagine this might be a CSS issue, but I appreciate the help!

Javascript

    const autoSlideshow = () => {
        const slides = document.querySelectorAll('.slides img')
        const slideDelay = 6000
        let currentSlide = 0
    
        slides[currentSlide].classList.add('.active')
    
        const nextSlide = () => {
            slides[currentSlide].classList.remove('.active')
            currentSlide = (currentSlide + 1) % slides.length
            slides[currentSlide].classList.add('.active')
        }
    
        setInterval(nextSlide, slideDelay)
    }
    autoSlideshow()

CSS

.slides img.active {
    opacity: 1;
    transition: opacity 2s ease-in-out;
}
.slides img {
    position: inherit;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
}

HTML

<div class="slides">
   <img src="img/ac62.jpg" alt="couple 1"> 
   <img src="img/b348.jpg" alt="couple 2">
   <img src="img/bk40.jpg" alt="couple 3">
</div>

Answer 1

Solution

const autoSlideshow = () => {
    const slides = document.querySelectorAll('.slides img')
    const slideDelay = 6000
    let currentSlide = 0

    slides[currentSlide].classList.add('active')

    const nextSlide = () => {
        slides[currentSlide].classList.remove('active')
        currentSlide = (currentSlide + 1) % slides.length
        slides[currentSlide].classList.add('active')
    }

    setInterval(nextSlide, slideDelay)
}
autoSlideshow()

replace .active with active

Answer 2

You need to remove . from .active while adding to or removing from classList. Because you are already doing classList.add / classList.remove , there is no need to define a class with .

 const autoSlideshow = () => { const slides = document.querySelectorAll('.slides img') const slideDelay = 6000 let currentSlide = 0 slides[currentSlide].classList.add('active') const nextSlide = () => { slides[currentSlide].classList.remove('active') currentSlide = (currentSlide + 1) % slides.length slides[currentSlide].classList.add('active') } setInterval(nextSlide, slideDelay) } autoSlideshow()

 .slides img.active { opacity: 1; transition: opacity 2s ease-in-out; }.slides img { position: inherit; width: 100%; height: 100%; object-fit: cover; opacity: 0; }

 <div class="slides"> <img src="https://source.unsplash.com/random" alt="couple 1"> <img src="https://source.unsplash.com/random" alt="couple 2"> <img src="https://source.unsplash.com/random" alt="couple 3"> </div>