javascript 右下角浮動視窗代碼

javascript 右下角浮動視窗代碼
var winWidth = 0;
var winHeight = 0;
var offsetBody=0;
function findDimensions(){
  if (window.innerWidth)
     winWidth = window.innerWidth;
  else if ((document.body) && (document.body.clientWidth))
     winWidth = document.body.clientWidth;
  if (window.innerHeight)
     winHeight = window.innerHeight;
  else if ((document.body) && (document.body.clientHeight))
     winHeight = document.body.clientHeight;
  if (document.documentElement && document.documentElement.clientHeight && document.documentElement.clientWidth){
   winHeight = document.documentElement.clientHeight;
   winWidth = document.documentElement.clientWidth;
  }
  offsetBody=Math.floor((document.documentElement.clientWidth-document.body.clientWidth)/2)
}
findDimensions();
window.onresize=findDimensions;//視窗調整時執行。得到瀏覽器寬度高度。

var delta=0.25;
var collection;
var closeB=false;
function floaters(winHeight) {
 this.items = [];
 this.addItem = function(id,x,y,content) {
  document.write('<div id=' + id + ' style="z-index: 10; position: absolute;  left:' + (typeof(x) == 'string' ? eval(x) : x) + ';top:' + (typeof(y) == 'string'? eval(y) : y) + '">' + content + '</div>');
  var newItem = {};
  newItem.object = document.getElementById(id);
  newItem.x = x;
  newItem.y = y;
  this.items[this.items.length] = newItem;
 }
 this.play = function() {
  collection = this.items;
  setInterval('play()',30);
 }
}
function play() {
 if(winWidth<= 950 || closeB) {
  for(var i = 0;i < collection.length;i++) {
   collection[i].object.style.display = 'none';
  }
  return;
 }
 for(var i = 0;i < collection.length;i++) {
  var followObj = collection[i].object;
  var followObj_x = (typeof(collection[i].x) == 'string' ? eval(collection[i].x) : collection[i].x);
  var followObj_y = (typeof(collection[i].y) == 'string' ? eval(collection[i].y) : collection[i].y);
  

  if(followObj.offsetLeft != (document.documentElement.scrollLeft + followObj_x - offsetBody)) {
   var dx = (document.documentElement.scrollLeft + followObj_x - followObj.offsetLeft-offsetBody) * delta;
   dx = (dx > 0 ? 1 : -1) * Math.ceil(Math.abs(dx));
   followObj.style.left = (followObj.offsetLeft + dx) + 'px';
  }
  if(followObj.offsetTop != (document.documentElement.scrollTop + followObj_y)) {
   var dy = (document.documentElement.scrollTop + followObj_y - followObj.offsetTop) * delta;
   dy = (dy > 0 ? 1 : -1) * Math.ceil(Math.abs(dy));
   followObj.style.top = (followObj.offsetTop + dy) + 'px';

  }
  followObj.style.display = '';
 }
}
function closeBanner() {
 closeB = true;
 return;
}
var theFloaters = new floaters(winHeight);