身份证有效性验证方法【javaScript】

 function(num) {
    //参数必须是字符串
    if (!(num === (num + ''))) {
        return false;
    }
    num = num.toUpperCase();
    //身份证号码为15位或者18位，15位时全为数字，18位前17位为数字，最后一位是校验位，可能为数字或字符X。
    if (!(/(^\d{15}$)|(^\d{17}([0-9]|X)$)/.test(num))) {
        //身份证号格式不符合规定！15位号码应全为数字，18位号码末位可以为数字或X;
        return false;
    }
    //校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。
    var city={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(!city[num.substr(0,2)]){
        return false;
    }
    //下面分别分析出生日期和校验位
    var len, re;
    len = num.length;
    if (len == 15) {
        re = new RegExp(/^(\d{6})(\d{2})(\d{2})(\d{2})(\d{3})$/);
        var arrSplit = num.match(re);
        //检查生日日期是否正确
        var dtmBirth = new Date('19' + arrSplit[2] + '/' + arrSplit[3] + '/' + arrSplit[4]);
        var bGoodDay;
        bGoodDay = (dtmBirth.getYear() == Number(arrSplit[2]))
            && ((dtmBirth.getMonth() + 1) == Number(arrSplit[3]))
            && (dtmBirth.getDate() == Number(arrSplit[4]));
        if (!bGoodDay) {
            //输入的身份证号里出生日期不对;
            return false;
        } else {
            //将15位身份证转成18位
            //校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。
            var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);
            var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');
            var nTemp = 0, i;
            num = num.substr(0, 6) + '19' + num.substr(6, num.length - 6);
            for (i = 0; i < 17; i++) {
                nTemp += num.substr(i, 1) * arrInt[i];
            }
            num += arrCh[nTemp % 11];
            len = num.length;
        }
    }

    if (len == 18) {
        re = new RegExp(/^(\d{6})(\d{4})(\d{2})(\d{2})(\d{3})([0-9]|X)$/);
        var arrSplit = num.match(re);
        //检查生日日期是否正确
        var dtmBirth = new Date(arrSplit[2] + "/" + arrSplit[3] + "/" + arrSplit[4]);
        var bGoodDay;
        bGoodDay = (dtmBirth.getFullYear() == Number(arrSplit[2]))
            && ((dtmBirth.getMonth() + 1) == Number(arrSplit[3]))
            && (dtmBirth.getDate() == Number(arrSplit[4]));
        if (!bGoodDay) {
            //输入的身份证号里出生日期不对;
            return false;
        } else {
            //检验18位身份证的校验码是否正确。
            //校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。
            var valnum;
            var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);
            var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');
            var nTemp = 0;
            for (var i = 0; i < 17; i++) {
                nTemp += num.substr(i, 1) * arrInt[i];
            }
            valnum = arrCh[nTemp % 11];
            if (valnum != num.substr(17, 1)) {
                //校验码不正确;
                return false;
            }
        }
    } else {
        return false;
    }

    return true;
};