我想把带有类"height_mark“的div从网页底部每隔980px放一次。

.height_mark {
  position: fixed;
  bottom: 0;
}

window.addEventListener('load', function() {
  var windowHeight = window.innerHeight;
  var divHeight = 100; // 假设div的高度为100px
  var gap = 980; // 间隔为980px

  var numDivs = Math.floor(windowHeight / gap); // 计算需要插入的div数量

  for (var i = 0; i < numDivs; i++) {
    var newDiv = document.createElement('div');
    newDiv.className = 'height_mark';
    newDiv.style.bottom = (i * gap + divHeight) + 'px';
    document.body.appendChild(newDiv);
  }
});