网页中页面浮动图标的简单实现

  < script language = " JavaScript " >     var delta = 0.5     var collection;     function  floaters() {        this.items     =  [];        this.addItem     =   function (id,x,y,content)                  {                    document.write( ' <DIV id='+id+' style="Z-INDEX: 10; POSITION: absolute;  width:80px; height:60px;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 + 100 ;                     this.items[this.items.length]         =  newItem;                  }        this.play     =   function ()                  {                    collection                 =  this.items                    setInterval( ' play()',10);                   }        }         function  play()        {             if (screen.width <= 800 )            {                 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.body.scrollLeft + followObj_x)) {                    var dx = (document.body.scrollLeft + followObj_x - followObj.offsetLeft) * delta;                    dx = (dx > 0 ? 1 : - 1 ) * Math.ceil(Math.abs(dx));                    followObj.style.left = followObj.offsetLeft + dx;                    }                  if (followObj.offsetTop! = (document.body.scrollTop + followObj_y)) {                    var dy = (document.body.scrollTop + followObj_y - followObj.offsetTop) * delta;                    dy = (dy > 0 ? 1 : - 1 ) * Math.ceil(Math.abs(dy));                    followObj.style.top = followObj.offsetTop + dy;                    }                followObj.style.display     =   ' ';             }        }                var theFloaters         =   new  floaters();    theFloaters.addItem( ' followDiv1','document.body.clientWidth-106',80,'<br><a href="list.asp?id=1437" ><img src=images/left1.gif  border=0></a>');     theFloaters.play();       </ script >