<div onmousemove="position();" onmouSEOut="hide();">abc</div>
<div id="tip" style="position: fixed; visibility: hidden;">that's abc!</div>
<script type="text/javascript">
  function position() {
    var d = document.getElementById('tip');
    d.style.visibility = 'visible';
    d.style.left = event.screenX + 'px';
    d.style.top = event.screenY + 'px';
  }
  function hide() {
    document.getElementById('tip').style.visibility = 'hidden';
  }
</script>

当用户将鼠标悬停在“ abc” div上时,“即abc！” div会显示在鼠标光标旁边(并紧随其后).