我刚刚实现了这个，也许你可以用我的方法。

假设我们有以下HTML:

<div id="out" style="overflow:auto"></div>

然后我们可以检查它是否滚动到底部:

var out = document.getElementById("out");
// allow 1px inaccuracy by adding 1
var isScrolledToBottom = out.scrollHeight - out.clientHeight <= out.scrollTop + 1;

scrollHeight gives you the height of the element, including any non visible area due to overflow. clientHeight gives you the CSS height or said in another way, the actual height of the element. Both methods returns the height without margin, so you needn't worry about that. scrollTop gives you the position of the vertical scroll. 0 is top and max is the scrollHeight of the element minus the element height itself. When using the scrollbar it can be difficult (it was in Chrome for me) to get the scrollbar all the way down to the bottom. so I threw in a 1px inaccuracy. So isScrolledToBottom will be true even if the scrollbar is 1px from the bottom. You can set this to whatever feels right to you.

然后，只需将元素的scrollTop设置为底部即可。

if(isScrolledToBottom)
    out.scrollTop = out.scrollHeight - out.clientHeight;

我已经为你做了一个小提琴的概念:http://jsfiddle.net/dotnetCarpenter/KpM5j/

编辑: 增加了代码片段以澄清当isScrolledToBottom为真时。

Stick scrollbar to bottom const out = document.getElementById("out") let c = 0 setInterval(function() { // allow 1px inaccuracy by adding 1 const isScrolledToBottom = out.scrollHeight - out.clientHeight <= out.scrollTop + 1 const newElement = document.createElement("div") newElement.textContent = format(c++, 'Bottom position:', out.scrollHeight - out.clientHeight, 'Scroll position:', out.scrollTop) out.appendChild(newElement) // scroll to bottom if isScrolledToBottom is true if (isScrolledToBottom) { out.scrollTop = out.scrollHeight - out.clientHeight } }, 500) function format () { return Array.prototype.slice.call(arguments).join(' ') } #out { height: 100px; } <div id="out" style="overflow:auto"></div> <p>To be clear: We want the scrollbar to stick to the bottom if we have scrolled all the way down. If we scroll up, then we don't want the content to move. </p>

这可能对你有帮助:

var element = document.getElementById("yourDivID");
element.scrollTop = element.scrollHeight;

[编辑]，为了匹配注释…

function updateScroll(){
    var element = document.getElementById("yourDivID");
    element.scrollTop = element.scrollHeight;
}

每当添加内容时，调用函数updateScroll()，或设置一个计时器:

//once a second
setInterval(updateScroll,1000);

如果你只想在用户没有移动的情况下更新:

var scrolled = false;
function updateScroll(){
    if(!scrolled){
        var element = document.getElementById("yourDivID");
        element.scrollTop = element.scrollHeight;
    }
}

$("#yourDivID").on('scroll', function(){
    scrolled=true;
});

Jim Hall的答案更可取，因为当你向上滚动时，它确实不会滚动到底部，它也是纯CSS。

然而，非常不幸的是，这不是一个稳定的解决方案:在chrome(可能是由于1像素的问题由dotnetCarpenter上面描述)，scrollTop行为不准确的1像素，即使没有用户交互(在元素添加)。你可以设置scrollTop = scrollHeight - clientHeight，但是当另一个元素被添加时，这将保持div的位置，也就是“保持自己在底部”功能不再工作了。

所以，简而言之，添加少量Javascript(唉)将修复这个问题并满足所有要求:

类似于https://codepen.io/anon/pen/pdrLEZ this(示例由Coo)，在添加一个元素到列表后，还可以执行以下操作:

container = ...
if(container.scrollHeight - container.clientHeight - container.scrollTop <= 29) {
    container.scrollTop = container.scrollHeight - container.clientHeight;
}

29是直线的高度。

因此，当用户向上滚动半行时(如果可能的话?)，Javascript将忽略它并滚动到底部。但我想这是可以忽略的。而且，它修复了Chrome 1px的东西。

这里有一个基于Ryan Hunt博客文章的解决方案。它取决于overflow-anchor CSS属性，该属性将滚动位置固定在滚动内容底部的元素上。

function addMessage() { const $message = document.createElement('div'); $message.className = 'message'; $message.innerText = `Random number = ${Math.ceil(Math.random() * 1000)}`; $messages.insertBefore($message, $anchor); // Trigger the scroll pinning when the scroller overflows if (!overflowing) { overflowing = isOverflowing($scroller); $scroller.scrollTop = $scroller.scrollHeight; } } function isOverflowing($el) { return $el.scrollHeight > $el.clientHeight; } const $scroller = document.querySelector('.scroller'); const $messages = document.querySelector('.messages'); const $anchor = document.querySelector('.anchor'); let overflowing = false; setInterval(addMessage, 1000); .scroller { overflow: auto; height: 90vh; max-height: 11em; background: #555; } .messages > * { overflow-anchor: none; } .anchor { overflow-anchor: auto; height: 1px; } .message { margin: .3em; padding: .5em; background: #eee; } <section class="scroller"> <div class="messages"> <div class="anchor"></div> </div> </section>

注意，overflow-anchor目前在Safari中不起作用。

以下是你所需要的(我尽了最大的努力，一路上进行了大量的谷歌搜索):

<html>
<head>
  <script>
    // no jquery, or other craziness. just
    // straight up vanilla javascript functions
    // to scroll a div's content to the bottom
    // if the user has not scrolled up.  Includes
    // a clickable "alert" for when "content" is
    // changed.

    // this should work for any kind of content
    // be it images, or links, or plain text
    // simply "append" the new element to the
    // div, and this will handle the rest as
    // proscribed.

    let scrolled = false; // at bottom?
    let scrolling = false; // scrolling in next msg?
    let listener = false; // does element have content changed listener?
    let contentChanged = false; // kind of obvious
    let alerted = false; // less obvious

    function innerHTMLChanged() {
      // this is here in case we want to
      // customize what goes on in here.
      // for now, just:
      contentChanged = true;
    }

    function scrollToBottom(id) {
      if (!id) { id = "scrollable_element"; }
      let DEBUG = 0; // change to 1 and open console
      let dstr = "";

      let e = document.getElementById(id);
      if (e) {
        if (!listener) {
          dstr += "content changed listener not active\n";
          e.addEventListener("DOMSubtreeModified", innerHTMLChanged);
          listener = true;
        } else {
          dstr += "content changed listener active\n";
        }
        let height = (e.scrollHeight - e.offsetHeight); // this isn't perfect
        let offset = (e.offsetHeight - e.clientHeight); // and does this fix it? seems to...
        let scrollMax = height + offset;

        dstr += "offsetHeight: " + e.offsetHeight + "\n";
        dstr += "clientHeight: " + e.clientHeight + "\n";
        dstr += "scrollHeight: " + e.scrollHeight + "\n";
        dstr += "scrollTop: " + e.scrollTop + "\n";
        dstr += "scrollMax: " + scrollMax + "\n";
        dstr += "offset: " + offset + "\n";
        dstr += "height: " + height + "\n";
        dstr += "contentChanged: " + contentChanged + "\n";

        if (!scrolled && !scrolling) {
          dstr += "user has not scrolled\n";
          if (e.scrollTop != scrollMax) {
            dstr += "scroll not at bottom\n";
            e.scroll({
              top: scrollMax,
              left: 0,
              behavior: "auto"
            })
            e.scrollTop = scrollMax;
            scrolling = true;
          } else {
            if (alerted) {
              dstr += "alert exists\n";
            } else {
              dstr += "alert does not exist\n";
            }
            if (contentChanged) { contentChanged = false; }
          }
        } else {
          dstr += "user scrolled away from bottom\n";
          if (!scrolling) {
            dstr += "not auto-scrolling\n";

            if (e.scrollTop >= scrollMax) {
              dstr += "scroll at bottom\n";
              scrolled = false;

              if (alerted) {
                dstr += "alert exists\n";
                let n = document.getElementById("alert");
                n.remove();
                alerted = false;
                contentChanged = false;
                scrolled = false;
              }
            } else {
              dstr += "scroll not at bottom\n";
              if (contentChanged) {
                dstr += "content changed\n";
                if (!alerted) {
                  dstr += "alert not displaying\n";
                  let n = document.createElement("div");
                  e.append(n);
                  n.id = "alert";
                  n.style.position = "absolute";
                  n.classList.add("normal-panel");
                  n.classList.add("clickable");
                  n.classList.add("blink");
                  n.innerHTML = "new content!";

                  let nposy = parseFloat(getComputedStyle(e).height) + 18;
                  let nposx = 18 + (parseFloat(getComputedStyle(e).width) / 2) - (parseFloat(getComputedStyle(n).width) / 2);
                  dstr += "nposx: " + nposx + "\n";
                  dstr += "nposy: " + nposy + "\n";
                  n.style.left = nposx;
                  n.style.top = nposy;

                  n.addEventListener("click", () => {
                    dstr += "clearing alert\n";
                    scrolled = false;
                    alerted = false;
                    contentChanged = false;
                    n.remove();
                  });

                  alerted = true;
                } else {
                  dstr += "alert already displayed\n";
                }
              } else {
                alerted = false;
              }
            }
          } else {
            dstr += "auto-scrolling\n";
            if (e.scrollTop >= scrollMax) {
              dstr += "done scrolling";
              scrolling = false;
              scrolled = false;
            } else {
              dstr += "still scrolling...\n";
            }
          }
        }
      }

      if (DEBUG && dstr) console.log("stb:\n" + dstr);

      setTimeout(() => { scrollToBottom(id); }, 50);
    }

    function scrollMessages(id) {
      if (!id) { id = "scrollable_element"; }
      let DEBUG = 1;
      let dstr = "";

      if (scrolled) {
        dstr += "already scrolled";
      } else {
        dstr += "got scrolled";
        scrolled = true;
      }
      dstr += "\n";

      if (contentChanged && alerted) {
        dstr += "content changed, and alerted\n";
        let n = document.getElementById("alert");
        if (n) {
          dstr += "alert div exists\n";
          let e = document.getElementById(id);
          let nposy = parseFloat(getComputedStyle(e).height) + 18;
          dstr += "nposy: " + nposy + "\n";
          n.style.top = nposy;
        } else {
          dstr += "alert div does not exist!\n";
        }
      } else {
        dstr += "content NOT changed, and not alerted";
      }

      if (DEBUG && dstr) console.log("sm: " + dstr);
    }

    setTimeout(() => { scrollToBottom("messages"); }, 1000);

    /////////////////////
    // HELPER FUNCTION
    //   simulates adding dynamic content to "chat" div
    let count = 0;
    function addContent() {
      let e = document.getElementById("messages");
      if (e) {
        let br = document.createElement("br");
        e.append("test " + count);
        e.append(br);
        count++;
      }
    }
  </script>

  <style>
    button {
      border-radius: 5px;
    }

    #container {
      padding: 5px;
    }

    #messages {
      background-color: blue;
      border: 1px inset black;
      border-radius: 3px;
      color: white;
      padding: 5px;
      overflow-x: none;
      overflow-y: auto;
      max-height: 100px;
      width: 100px;
      margin-bottom: 5px;
      text-align: left;
    }

    .bordered {
      border: 1px solid black;
      border-radius: 5px;
    }

    .inline-block {
      display: inline-block;
    }

    .centered {
      text-align: center;
    }

    .normal-panel {
      background-color: #888888;
      border: 1px solid black;
      border-radius: 5px;
      padding: 2px;
    }

    .clickable {
      cursor: pointer;
    }
  </style>
</head>
<body>
<div id="container" class="bordered inline-block centered">
  <div class="inline-block">My Chat</div>

  <div id="messages" onscroll="scrollMessages('messages')">
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
    test<br>
  </div>

  <button onclick="addContent();">Add Content</button>
</div>
</body>
</html>

注意:你可能需要在scrollToBottom和scrollMessages中调整警报位置(nposx和nposy)来匹配你的需求…

还有一个链接到我自己的工作示例，托管在我的服务器上:https://night-stand.ca/jaretts_tests/chat_scroll.html

$('#yourDiv').scrollTop($('#yourDiv')[0].scrollHeight);

现场演示:http://jsfiddle.net/KGfG2/