title.addEventListener("click", handleTitleClick); //.removeEventListener 이런게 가능해서 addEventListener 선호 //title.onclick = handleTitleClick; function handleTitleClick() { const clickedClass = "clicked sexy-font"; if (h1.classList.contains(clickedClass)) { h1.className = ""; } else { h1.className = clickedClass; } } h1.addEventListener("click", handleTitleClick); DOCTYPE html> Momentum Click me! cl..