How can I edit the styles from a 'click button' event I want to make a side menu when I give ami boton I want to use a div so that the menu comes out

quiero pasar mi codigo js en un evento de meteor

function openNav() {
document.getElementById(“mySidenav”).style.width = “250px”;
}
function closeNav() {
document.getElementById(“mySidenav”).style.width = “0”;
}

read here: https://www.meteor.com/tutorials/blaze/forms-and-events