SOURCE

let e = document.getElementById('content')
e.addEventListener('mousewheel', function (e) {
  let element = document.getElementById('content')
  let stepLen = 50
	let delD = e.wheelDelta ? e.wheelDelta : -e.detail * 40
  let moves = delD > 0 ? -stepLen : stepLen
  element.scrollLeft += moves
  
  let info = `offsetWidth: ${element.offsetWidth}, scrollLeft: ${element.scrollLeft}, scrollWidth: ${element.scrollWidth}`
  document.getElementById('info').innerHTML = info
  if (_wheelEnd(element)) {
    document.getElementById('info').innerHTML += '到底啦！'
  }
}, false)

function _wheelEnd (e) {
  return (e.scrollLeft + e.offsetWidth) >= e.scrollWidth
}

<ul id="content">
    <li></li>
  </ul>
<h3>
  结果：
</h3>
<div id="info">
</div>

ul {
  margin: 0 auto;
  padding: 0;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  border: 1px solid;
  overflow-y: hidden;
}
li {
  list-style: none;
  width: 1000px;
  height: 200px;
  background-color: #000;
}
#info {
  margin: 0 auto;
  width: 400px;
  height: 100px;
  /* border: 1px solid blue; */
  margin-top: 20px;
}