<script language="JavaScript">
document.write('<div id=\"china_ads_div405\">');
document.writeln("<a href=\"tencent:\/\/message\/?uin=840353522&Site=http:\/\/www.yyqq.com\/&Menu=yes\" target=\"_blank\"><img src=\"http:\/\/i3.6.cn\/cvbnm\/1a\/5b\/08\/d4de73f843cc37ac60da3de5a0224e42.jpg\" width=\"200\" height=\"150\" ");
document.writeln("border=\"0\"><\/a><\/div>")
    var Class = {
      create: function() {
        return function() {
          this.initialize.apply(this, arguments);
        }
      }
    }
    
    Function.prototype.bind = function() {
      var __method = this, args = $A(arguments), object = args.shift();
      return function() {
        return __method.apply(object, args.concat($A(arguments)));
      }
    }
    
    var $A = Array.from = function(iterable) {
      if (!iterable) return [];
      if (iterable.toArray) {
        return iterable.toArray();
      } else {
        var results = [];
        for (var i = 0; i < iterable.length; i++)
          results.push(iterable[i]);
        return results;
      }
    }
    var Float = Class.create();
    Float.prototype = {
        initialize: function(elem, options) {
            this.toDo = options.toDo || function(){},
            this.bodyScrollTop = document.documentElement.scrollTop || document.body.scrollTop,
            this.bodyScrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft,
            this.element = document.getElementById(elem);
            this.dely = options.dely || 500;
            this.top = options.top || 0;
            this.left = options.left || 0;
            
        },
        
        start:function(){
            if(!this.element){
                alert('please set a element first!');
                return false;
            }
            this.element.style.position = 'absolute';
            this.toDo();
            setInterval(this.toDo.bind(this),this.dely)
        }
    }
    
var f = new Float('china_ads_div405',{dely:100,
    toDo:function(){
        var isIE = document.all && window.external;
        this.bodyScrollTop = document.documentElement.scrollTop || document.body.scrollTop;
        this.bodyScrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft;
        if(isIE){
            this.docWidth = document.documentElement.clientWidth || document.body.clientWidth;
            this.docHeight = document.documentElement.clientHeight || document.body.clientHeight;
        }else{
            this.docWidth = (document.body.clientWidth > document.documentElement.clientWidth)?document.documentElement.clientWidth:document.body.clientWidth;
            this.docHeight = (document.body.clientHeight > document.documentElement.clientHeight)?document.documentElement.clientHeight:document.body.clientHeight;
        }
        this.element.style.top = (this.docHeight - parseInt(this.element.offsetHeight,10)) + parseInt(this.bodyScrollTop, 10)+ 'px';
        this.element.style.left = (this.docWidth - parseInt(this.element.offsetWidth,10)) + parseInt(this.bodyScrollLeft, 10) + 'px';
    }
});
f.start();
</script>

------解决方案--------------------
http://topic.csdn.net/u/20080910/21/bf2b827f-a302-42aa-a8e3-6467c8d9aea5.html