javascript 新浪背投广告实现代码

/*
轮播背投类 RotatorPB v3.1
Update by Dakular <shuhu@staff.sina.com.cn> 2008-8-25
格式：new RotatorPB(广告数组)
说明：第一次访问随机出现，以后访问顺序轮播；自动过滤过期广告；cookie时间24小时；商业广告数量不足时不显示
*/
if(typeof(RotatorPB)!='function'){
    var RotatorPB=function (rad){
        this.ary = new Array();
        this.date = new Date();
        this.w = rad.width;
        this.h = rad.height;
        this.num = rad.num;
        this.o = rad.length;
        this.id = RotatorPB.id++;
        this.m = 'rpb_'+this.id;
        this.n = new Array();
        this.L = new Date();
        this.e = 0;
        var f;
        var D = false;
        var nn = 0;
        //过滤无效广告
        for(var i=0; i<rad.length; i++){
            var start = RotatorPB.strToDate(rad[i][2].replace('<startdate>','').replace('</startdate>',''));
            var end = RotatorPB.strToDate(rad[i][3].replace('<enddate>','').replace('</enddate>',''),true);
            if(this.date>start && this.date<end && (this.num==null || this.ary.length<this.num) ){
                this.ary.push([rad[i][0], rad[i][1], rad[i][4]]);
            }
        }
        this.o = this.ary.length;
        //取id
        for(var i=0;i<this.o;i++){
            f=this.m+'_'+(i+1);
            g=RotatorPB.G(f);
            if(g!=''){
                this.n[i]=g;
                D=true;
            }else {
                this.n[i]=0;
            }
        }
        if(!D){
            var r=Math.ceil(Math.random()*this.o);
            var t=this.m+'_'+r;
            RotatorPB.S(t,this.L.getTime(),1440);
            this.e=r;
            if(this.o==1){RotatorPB.S('s_dl',r,1440);}
            //return r;
        }else {
            var R=this.n.join(',').split(',');
            var k=R.sort();
            var max=Number(k[k.length-1]);
            var min=Number(k[0]);
            var F;
            for(var i=0;i<this.n.length;i++){
                if(max==this.n[i]){
                    F=i+1;
                    break;
                }
            }
            if(typeof(F)!='undefined'){
                G=this.m+'_'+F;
                H=Number(RotatorPB.G(G));
                I=F%this.o+1;
                J=this.m+'_'+I;
                RotatorPB.S(J,this.L.getTime(),1440);
                if(this.o==1){
                    I=-RotatorPB.G('s_dl');
                    if(I==0){I=1;RotatorPB.S('s_dl',1,1440);}
                    RotatorPB.S('s_dl',I,1440);
                }
                this.e=I;
                //return I;
            }
        }
        //Show AD
        if(this.e==0 || this.ary.length==0) return; //如果没有广告则不显示
        if(this.e==-1) return; //当只有一个广告时：始终显示第一个/奇数次刷新显示
        var n = this.e-1;
        var btsrc = this.ary[n][0];
        var bturl = this.ary[n][1];
        var bttype = btsrc.substring(btsrc.length-3).toLowerCase();
        if(bttype=='.js'){ //js
            document.write('<script language="javascript" type="text/javascript" src="'+btsrc+'"></scr'+'ipt>'); return;
        }else if(bttype!='htm' && bttype!='tml'){
            sinabturl = "http://d1.sina.com.cn/d1images/pb/pbv4.html?"+bturl+"${}"+bttype+"${}"+btsrc;
        }else{
            sinabturl = btsrc;
        }
        try{
            aryADSeq.push("openWindowBack()");
        }catch(e){
            openWindowBack();
        }
        if(this.ary[n][2]!=""){ //监测计数
            var oImg = new Image();
            oImg.src = this.ary[n][2];
        }
    };
    RotatorPB.id=1;
    RotatorPB.G=function (N){
        var c=document.cookie.split("; ");
        for(var i=0;i<c.length;i++){
            var d=c[i].split("=");
            if(d[0]==N)return unescape(d[1]);
        }return '';
    };
    RotatorPB.S=function (N,V,Q){
        var L=new Date();
        var z=new Date(L.getTime()+Q*60000);
        document.cookie=N+"="+escape(V)+"; path=/; expires="+z.toGMTString()+";";
    };
    RotatorPB.strToDate = function(str,ext){
        var arys = new Array();
        arys = str.split('-');
        var newDate = new Date(arys[0],arys[1]-1,arys[2],9,0,0);
        if(ext){
            newDate = new Date(newDate.getTime()+1000*60*60*24);
        }
        return newDate;
    }
    var openWindowBack = function(){
        var popUpWin2 = open(sinabturl, (window.name!="popUpWin2")?"popUpWin2":"", "width=1,height=1,top=4000,left=3000");
    }
};

<script src="rotator_pb.js"></script>
<SCRIPT language=javascript type=text/javascript>
//<![CDATA[
var rpb = new Array();
rpb.num = 2; //轮播数量
<!--2220E7B88D58-->//背投广告创意
rpb.push(["http://img.jb51.net/demo/images/beitou.jpg", "https://www.jb51.net", "<startdate>2009-4-15</startdate>", "<enddate>2009-8-15</enddate>", ""]);
<!--$$ litong/2009-4-15 ~ 2009-8-15/B $-->
new RotatorPB(rpb);
//]]>
</SCRIPT>