function openMenu(menu) {
var submenu = menu.children[1];
menu.addEventListener('click', function(){
submenu.classList.toggle('active');
});
}
function openMenu(menu) {
var submenu = menu.children[1];
document.getElementsByClassName("menu_1")[0].addEventListener("click", openMenu);
function openMenu() {
document.getElementsByClassName("dropdown")[0].classList.toggle("active");
}
https://jsfiddle.net/pzawLfgz/253/