javascript 浮动窗口滚动.拖动

<script type="text/javascript">
 function close(){
  QQkefu.style.display="none";
  return true;
 }
  function msgBox()
 {
  this.container = "aaaa";
  this.titleheadArea = "titlehead";
  this.width = 154;
  this.height = 105;
  this.smallHeight = 20;
  this.smallId = "small";
  this.area = ( document.compatMode.toLowerCase()=="css1compat" ) ? document.documentElement : document.body;
  this.space = 5;
  this.timer;
  this.timeOut = 150;
  this.smalled = false;
  window.msgBoxListener = this;
  this.$(this.smallId).onclick= function(){msgBoxListener.toSmall()};
 }
 msgBox.prototype.flow = function()
 {
  this.$(this.container).style.position = "absolute";
  this.$(this.container).style.zIndex = "1000";
  if(this.smalled)
  {
   this.$(this.container).style.top = this.area.scrollTop + this.area.clientHeight - this.smallHeight - this.space + "px";
  }else{
   this.$(this.container).style.top = this.area.scrollTop + this.area.clientHeight - this.height - this.space + "px";
  }
   this.$(this.container).style.left = this.area.scrollLeft + this.area.clientWidth - this.width - this.space + "px";
  }
  msgBox.prototype.toSmall = function()
  {
   if(this.smalled)
   {
    this.$(this.container).style.marginTop = -this.height + "px";
    this.$(this.container).style.height = this.height + "px";
     this.smalled = false;
    this.flow();
    this.$(this.container).style.marginTop = "0px";
   }else{
    th