//<div class="warning">
// <div id="w1" class = "warn"></div>
// <div id="w2" class = "warn"></div>
// <div id="w3" class = "warn"></div>
//</div>
let element = document.querySelectorAll('.warn');
console.log(element);
let r_first_warn = element[0];
let r_second_warn = element[1];
let r_third_warn = element[2];
r_first_warn.onclick = function () {
document.querySelector('#w1').classList.add('.lamp');
}
document.querySelector('#w1').classList.add('lamp');