Attr selected

const selectHTML = document.getElementById("cities");
let prevValue = null;

selectHTML.addEventListener("change", () => {
  if(prevValue !== null) {
    console.log(selectHTML.children[prevValue]);
    selectHTML.children[prevValue].removeAttribute("selected");
  }
  val = selectHTML.value - 1;
  selectHTML.children[val].setAttribute("selected", "");
  prevValue = val;
});