It should work the same way as:

How this one works:

window.onload = function() {
const container = document.querySelector(".video-containerA");
const spinner = document.querySelector(".spinner");
const exitButton = document.querySelector(".exitA");

spinner.addEventListener("animationend", function() {
container.classList.add("slide");
});

container.addEventListener("transitionend", function() {
exitButton.classList.add("visible");
});
};

After clicking the exit button the curtain should go up.

After it is up, exit button should be visible

How do I fix this: https://jsfiddle.net/96fm3rhv/10/

I am confused here.

The curtain is not going up.

I don’t understand, it should be working.

function showContainer(containerSelector, spinnerSelector, exitSelector) {
    const container = document.querySelector(containerSelector);
    const exitButton = document.querySelector(exitSelector);

    container.classList.remove("hide");

    const spinner = document.querySelector(spinnerSelector);
    spinner.addEventListener("animationend", function() {
      container.classList.add("slide");
    });

    container.addEventListener("animationend", function() {
      exitButton.classList.add("visible");
    });
}