是否是有效的身份证(中国)

/*
===========================================
//是否是有效的身份证(中国)
===========================================
*/
String.prototype.isIDCard = function()
{
        var iSum=0;
        var info="";
        var sId = this;

        var aCity={11:"北京",12:"天津",13:"河北",14:"山西",15:"内蒙古",21:"辽宁",22:"吉林",23:"黑龙 江",31:"上海",32:"江苏",33:"浙江",34:"安徽",35:"福建",36:"江西",37:"山东",41:"河南",42:"湖 北",43:"湖南",44:"广东",45:"广西",46:"海南",50:"重庆",51:"四川",52:"贵州",53:"云南",54:"西 藏",61:"陕西",62:"甘肃",63:"青海",64:"宁夏",65:"新疆",71:"台湾",81:"香港",82:"澳门",91:"国 外"};

        if(!/^/d{17}(/d|x)$/i.test(sId))
        {
                return false;
        }
        sId=sId.replace(/x$/i,"a");
        //非法地区
        if(aCity[parseInt(sId.substr(0,2))]==null)
        {
                return false;
        }

        var sBirthday=sId.substr(6,4)+"-"+Number(sId.substr(10,2))+"-"+Number(sId.substr(12,2));

        var d=new Date(sBirthday.replace(/-/g,"/"))
      
        //非法生日
        if(sBirthday!=(d.getFullYear()+"-"+ (d.getMonth()+1) + "-" + d.getDate()))
        {
                return false;
        }
        for(var i = 17;i>=0;i--)
        {
                iSum += (Math.pow(2,i) % 11) * parseInt(sId.charAt(17 - i),11);
        }

        if(iSum%11!=1)
        {
                return false;
        }
        return true;

}