子导航点的递减div宽度

.subnav-item {
  background-color: #ccc;
  width: 100px;
  border: 1px solid #000;
}

var subnavItems = document.getElementsByClassName('subnav-item');

for (var i = 0; i < subnavItems.length; i++) {
  subnavItems[i].addEventListener('click', function() {
    var width = 100; // 初始宽度
    var interval = setInterval(function() {
      width -= 10; // 每次减少的宽度
      if (width <= 0) {
        clearInterval(interval);
      }
      this.style.width = width + 'px';
    }, 100); // 每次减少的时间间隔
  });
}