JS中校验身份证号码是否合法

//身份证号合法性验证
//支持18位身份证号
//支持地址编码、出生日期、校验位验证
function isIdCardNo(code) {
    var flag=true;
    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"};
    var iSum = 0;
    var strIDno = code;
    var idCardLength = strIDno.length;
    if(!/^\d{17}(\d|x)$/i.test(strIDno)&&!/^\d{15}$/i.test(strIDno)){
        flag=false; //非法身份证号
    }
    if(aCity[parseInt(strIDno.substr(0,2))]==null){
        flag=false;
    }
    // 15位身份证转换为18位
    if (idCardLength==15)
    {
        sBirthday = "19" + strIDno.substr(6,2) + "-" + Number(strIDno.substr(8,2)) + "-" + Number(strIDno.substr(10,2));
        var d = new Date(sBirthday.replace(/-/g,"/"))
        var dd = d.getFullYear().toString() + "-" + (d.getMonth()+1) + "-" + d.getDate();
        if(sBirthday != dd){
            flag=false;
        }
        strIDno=strIDno.substring(0,6)+"19"+strIDno.substring(6,15);
        strIDno=strIDno+GetVerifyBit(strIDno);
    }

    // 判断是否大于2078年，小于1900年
    var year =strIDno.substring(6,10);
    if (year<1900 || year>2078 ){
        flag=false;
    }

    //18位身份证处理
    //在后面的运算中x相当于数字10,所以转换成a
    strIDno = strIDno.replace(/x$/i,"a");
    sBirthday=strIDno.substr(6,4)+"-"+Number(strIDno.substr(10,2))+"-"+Number(strIDno.substr(12,2));
    var d = new Date(sBirthday.replace(/-/g,"/"))
    if(sBirthday!=(d.getFullYear()+"-"+ (d.getMonth()+1) + "-" + d.getDate())){
        flag=false;
    }
    // 身份证编码规范验证
    for(var i = 17;i>=0;i --)
        iSum += (Math.pow(2,i) % 11) * parseInt(strIDno.charAt(17 - i),11);
    if(iSum%11!=1){
        flag=false;
    }
    // 判断是否屏蔽身份证
    var words = new Array();
    words = new Array("11111119111111111","12121219121212121");
    for(var k=0;k<words.length;k++){
        if (strIDno.indexOf(words[k])!=-1){
            return 1;
        }
    }
    return flag;
}