How can I change a Pseudo-class element with JavaScript?

Question

How can I chnage a Pseduo-class, like ::after, in Javscript in the following 5 seconds, considering that I want to build a a start-up transition .

I want to chnage .title::after's left from 69% to -50vh . I tried to select .title::after with querySelector, but it didn't work . I tried of course to search what I want to do but I eneded up with nothing functional .

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="index.css">
</head>
<body>
    <div class="content">
        <div class="intro">
            <h1  class="title">Programming</h1>       
            <h3 class="subtitle">REINVENTED</h3>  
        </div>
    </div>
    <script src="index.js"></script>
</body>
</html>

CSS:

body {
    font-family: 'Montserrat', sans-serif;
    background: #141414;
    width: 100%;
    height: 100%;
    overflow: hidden;

}
.intro {
    mask: url(.mask);
    mask-type: luminance;
    mask-mode: alpha;
    margin: 0;
    position: absolute;
    top: 50%;
    left: 40%;
    transform: translate(-50%, -50%);

}
.intro h1 {
    color: white;
    font-weight: 800;
    font-size: 7em;
}
.intro h3 {
    color: white;
    font-weight: 300;
    font-size: 3.5em;
    position: absolute;
    left: 37.7vw;
    top: 20vh;
}

.intro h1::after {
    content: "";
    backdrop-filter: invert(100%);
    position: absolute;
    bottom: -50vh;
    left: 69%;
    margin-left: -50px;
    width: 320px;
    height: 150vh;
    z-index: 2;
    transition-delay: 2s;
    transition-duration: 1s;
    transition-timing-function: ease-in-out;
  }
  .transitioned {
    content: "";
    backdrop-filter: invert(100%);
    position: absolute;
    bottom: -50vh;
    left: -320PX;
    margin-left: -50px;
    width: 320px;
    height: 150vh;
    z-index: 2;
  }

You can't. Pseudo elements are not in the DOM and so cannot be selected by Javascript — Paulie_D, Apr 21 '20 at 18:48
You can do it by adding class using javascript to the element whose pseudo element you want to change. And then change the styling like so => h1.title.added_class::after{..} — Adnan, Apr 21 '20 at 19:50
Thank you for your time, I will try to make it work . Have a great day ! — Andrei Bunea, Apr 21 '20 at 20:33

How can I change a Pseudo-class element with JavaScript?

0 Answers0