点击时如何在锚点标签上添加活动类？

<a id="link1" href="#section1">Section 1</a>

var link1 = document.getElementById("link1");
link1.addEventListener("click", function() {
  // 移除其他锚点标签的活动类
  var links = document.getElementsByTagName("a");
  for (var i = 0; i < links.length; i++) {
    links[i].classList.remove("active");
  }
  
  // 为当前点击的锚点标签添加活动类
  link1.classList.add("active");
});

.active {
  color: red;
  font-weight: bold;
}