js 身份证校验

IdentityCodeValid(code) {
    let 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 "
    };
    let tip = "";
    let pass = true;

    if (!code || !/^\d{6}(18|19|20)?\d{2}(0[1-9]|1[0-2])(0[1-9]|[12]\d|3[01])\d{3}(\d|X)$/i.test(code)) {
        tip = "身份证号格式错误";
        pass = false;
    } else if (!city[code.substr(0, 2)]) {
        tip = "地址编码错误";
        pass = false;
    } else {
        //18位身份证需要验证最后一位校验位
        if (code.length == 18) {
            code = code.split('');
            //∑(ai×Wi)(mod 11)
            //加权因子
            let factor = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
            //校验位
            let parity = [1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2];
            let sum = 0;
            let ai = 0;
            let wi = 0;
            for (let i = 0; i < 17; i++) {
                ai = code[i];
                wi = factor[i];
                sum += ai * wi;
            }
            let last = parity[sum % 11];
            if (parity[sum % 11] != code[17]) {
                tip = "校验位错误";
                pass = false;
            }
        }
    }
    if (!pass) {
        alert(tip + '，请输入合法的身份证号码');

    }
    return pass;
},