苦恼了1个星期的DIV 滚动条置底, 今天终于实现了！

<script type="text/javascript" language="javascript">
    //DIV的滚动条始终显示聊天窗口最底部 
      function  setDIV()  {
            var div = document.getElementById('msg');
            div.scrollTop = div.scrollHeight; 
			//切忌setTimeout一定要放在这里，勿放onload里面，否则div的滚动条只能指在倒数第2行       
			 setTimeout('setDIV()', 200);
      }
       window.onload = function() {setDIV();}
</script>

<div id="msg" style="width: 420px; height: 150px; overflow-y: scroll; border: 1px solid #999; overflow: auto; background-color: #FFFFFF">
</div>

<input type="button" value="发送" onclick="setDIV();">

(function(){
      var div = document.getElementById('ff');
      setInterval(function(){div.scrollTop = div.scrollHeight;},200);
})();