html скрыть элемент
document.getElementById('elementId').style.display = "none";
Skynet
document.getElementById('elementId').style.display = "none";#elementID{
display:none;
}const targetDiv = document.getElementById("third");
const btn = document.getElementById("toggle");
btn.onclick = function () {
if (targetDiv.style.display !== "none") {
targetDiv.style.display = "none";
} else {
targetDiv.style.display = "block";
}
};