Empresas
Empregos
  • Sobre nós
  • Soluções
    • Publicação de vagas
      Publique sua vaga e receba candidatos qualificados em 48h.
    • Avaliações de candidatos
      Mais de 500 testes técnicos e psicológicos, mais anti-fraude.
    • Headhunting
      Busca executiva personalizada do início ao fim.
    • Folha de Pagamento + EOR
      Dispersão de folha e EOR em mais de 15 países da LATAM.
  • Preços
  • Empregos

0

206
Visualizações
add class to element in viewport

I have five sections on my page, and I am trying to add class "active" to the section in the view port. I tried this code but it is not working properly. the code saves all elements with tag name "section" in a node list then created an array of this list, I looped over the array and added an event listener for each element, then I tested if the element is in the viewport is so I add the class else I remove the class. the problem is once the page is scrolled all the five sections will have the class "active" which means that multiple elements have the class "active" at the same time even though only one section is viewed in the port and when I keep on scrolling down the sections that are moved upward out of the viewport have their class "active" removed. how can i have one element with the class "active"image of code at a time?

//values of viewport
const viewWidth = document.documentElement.clientWidth;
const viewHeight = document.documentElement.clientHeight;

//set class active to section in viewport
function sectionInView(x) {
    for (let i = 0; i in x; i++) {
        document.addEventListener("scroll", function () {
            let el = x[i].getBoundingClientRect();
            if (el.top >= 0 && el.left >= 0 && el.bottom <= viewHeight && el.right <= viewWidth) {
                x[i].setAttribute("class", "active your-active-class");

            }
            else {

                x[i].removeAttribute("class", "active your-active-class");
            }
        });
    }
}
sectionInView(sectionListArray);
about 4 years ago · Juan Pablo Isaza
1 Respostas
Responde à pergunta

0

let sectionListArray = document.querySelectorAll('section')
const viewHeight = document.documentElement.clientHeight
         window.onscroll = (() => {
            sectionListArray.forEach(function(v) {
                let rect = v.getBoundingClientRect();
                let y = rect.y;
                let bottom = rect.bottom;
                let height = rect.height;
                if (y > viewHeight|| bottom+height < viewHeight ) {
                    v.classList.add('active')
                } else {
                    v.classList.remove('active')
                }
            })
        })
        
section {
            height: 300px;
            background: red;
            margin-bottom: 10px;
            transition: 1s;
            opacity:1
        }
.active{
opacity:0
}
<section></section>
<section></section>
<section></section>
<section></section>
<section></section>
<section></section>
<section></section>
<section></section>
<section></section>

about 4 years ago · Juan Pablo Isaza Relatório
Responde à pergunta
Encontrar trabalhos remotos

Descubra a nova forma de encontrar um emprego!

melhores empregos
Principais categorias de trabalho
Empresas
Postar vaga Preços Comercial
Jurídico
Termos e Condições Política de privacidade
© 2026 PeakU Inc. All Rights Reserved.
Andres GPT
Recomende algumas ofertas para mim
Preciso de ajuda