产品对比效果的实现

function compareObject(compareObject_name)  
{  
    //init
    document.domain="360buy.com";
    this.initScrollY=0;
    this.proIDs=new Array(); 
    this.myName=compareObject_name;
}
compareObject.prototype={  
  compare:function()
    {
        if($("#compare").get(0)==null)
        {
            $("body").append("<div id=\"compare\" class=\"compare\"><div class=\"mt\"><h5>商品比较</h5><div class=\"extra\" onclick=\""+this.myName+".clearCompare()\"></div></div><div class=\"comPro\"><ul class=\"mc\" id=\"comProlist\"></ul><div class=\"mb\"><input type=\"button\" value=\"对比所选商品\" class=\"btn\" id=\"compareImg\" onclick=\""+this.myName+".openCompare()\"></div></div></div>");
            $("#compare").css(
            {
                position:"absolute",top:"190px",right:"0px"
            }
            );
            this.isCoo()
        }
        if($.browser.msie)
        {
            var defaultY=document.documentElement.scrollTop;
            var perceH=0.3*(defaultY-this.initScrollY);
            if(perceH>0)
            {
                perceH=Math.ceil(perceH)
            }
            else
            {
                perceH=Math.floor(perceH)
            }
            $("#compare").get(0).style.top=parseInt($("#compare").get(0).style.top)+perceH+"px";
            this.initScrollY=this.initScrollY+perceH;
            setTimeout(this.myName+".compare()",50)
        }
        else
        {
            window.onscroll=function()
            {
                $("#compare").get(0).style.top=parseInt($("#compare").get(0).style.top)+"px";
                $("#compare").get(0).style.position="fixed"
            }
        }
    },  
 clearCompare:function()
    {
        $("#comProlist").empty();
        $("#compare").hide();
        this.createCookie("compare","");
        this.proIDs=new Array();
    },
callback1:function(data){alert(data.name);}
get_ms:function(checkid1) {
    var url="http://www.360buy.com/lishiset.aspx?id="+checkid1+"&callback=callback1";
    $.getJSON(url,this.callback1)
},
addToCompare:function (checkobj,checkid,checkProName)
    {
    var checkProName=this.get_ms(checkid);
    $("#compare").show();
    $(".comPro").show();
    var proIDsTemp=this.proIDs.join(".");
    if(proIDsTemp.indexOf(checkid)==-1)
    {
        if(this.proIDs.length<3)
        {    
            var checkProName="http://www.360buy.com/lishiset.aspx?id="+this.checkid+"&callback="+jdRecent.get_ms; 
            this.proIDs.push(checkid);
            $("#comProlist").append("<li id='check_"+checkid+"'><a title='删除' class='close' onclick='"+this.myName+".reduceCompare("+checkid+")'></a>"+checkProName+"</li>");
            this.writeCompare(checkid,checkProName)
        }
        else
        {
            alert("对不起，最多可以选择三种商品进行对比！")
        }
    }
    else
    {
        alert("对不起，您已经选择此商品！");
        return
    }
    },
reduceCompare:function (checkid)
    {
    $("#check_"+checkid).remove();
    $.each(this.proIDs,function(i,n)
    {
        if(checkid==n)
        {
            this.proIDs.splice(i,1)
        }
    }
    );
    var coo=this.readCookie("compare");
    var idindexstart=coo.indexOf(checkid);
    var idindexend=coo.indexOf("|||",idindexstart)+3;
    var delStr=coo.substring(idindexstart,idindexend);
    var innerStr=coo.replace(delStr,"");
    this.createCookie("compare",innerStr);
    if(this.proIDs.length==0)
    {
        $(".comPro").hide()
    }
    },
openCompare:function()
    {
    switch(this.proIDs.length)
    {
        case 1:alert("对不起，最少选择两种商品进行对比！");
        break;
        case 2:window.open("http://www.360buy.com/pcompare.aspx?s1="+this.proIDs[0]+"&s2="+this.proIDs[1]);
        break;
        case 3:window.open("http://www.360buy.com/pcompare.aspx?s1="+this.proIDs[0]+"&s2="+this.proIDs[1]+"&s3="+this.proIDs[2]);
        break;
        default:alert("请选择2-3件商品进行对比！");
        return
    }
    },
writeCompare:function (checkid,checkProName)
    {
    var compareList=this.readCookie("compare");
    if(compareList==null)
    {
        compareList=""
    }
    compareList+=checkid+"||"+escape(checkProName)+"|||";
    this.createCookie("compare",compareList)
    },
    isCoo:function()
    {
    var coo=this.readCookie("compare");
    if(coo)
    {
        var cootemp=coo.split("|||");
        var compareListTemp="";
        for(var i=0;i<cootemp.length-1;i++)
        {
            compareListTemp+="<li id='check_"+cootemp[i].split("||")[0]+"'><a title='删除' class='close' onclick='"+this.myName+".reduceCompare("+cootemp[i].split("||")[0]+")'></a>"+unescape(cootemp[i].split("||")[1])+"</li>";
            this.proIDs.push(cootemp[i].split("||")[0])
        }
        $("#comProlist").html(compareListTemp);
        $("#compare").show();
        $(".comPro").show()
    }
    },
createCookie:function (name,value,days,Tdom)
    {
    var Tdom=(Tdom)?Tdom:"/";
    if(days)
    {
        var date=new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires="; expires="+date.toGMTString()
    }
    else
    {
        var expires=""
    }
    document.cookie=name+"="+value+expires+"; path="+Tdom
    },
readCookie:function (name)
    {
    var nameEQ=name+"=";
    var ca=document.cookie.split(';');
    for(var i=0;i<ca.length;i++)
    {
        var c=ca[i];
        while(c.charAt(0)==' ')
        {
            c=c.substring(1,c.length)
        }
        if(c.indexOf(nameEQ)==0)
        {
            return c.substring(nameEQ.length,c.length)
        }
    }
    return null
    }
}