公民身份号码正确性判定JavaScript演示程序

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>三十课-公民身份号码正确性判定JavaScript演示程序</title>
</head>
<body>
<div id="main"></div>
<script>
    console.log = function(val) {
        document.getElementById("main").innerHTML += val +"<br />";
    }
    var checkCode = function (val) {
        var p = /^[1-9]\d{5}(18|19|20)\d{2}((0[1-9])|(1[0-2]))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$/;
        var factor = [ 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2 ];
        var parity = [ 1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2 ];
        var code = val.substring(17);
        if(p.test(val)) {
            var sum = 0;
            for(var i=0;i<17;i++) {
                sum += val[i]*factor[i];
            }
            if(parity[sum % 11] == code.toUpperCase()) {
                return true;
            }
        }
        return false;
    }
    var checkDate = function (val) {
        var pattern = /^(18|19|20)\d{2}((0[1-9])|(1[0-2]))(([0-2][1-9])|10|20|30|31)$/;
        if(pattern.test(val)) {
            var year = val.substring(0, 4);
            var month = val.substring(4, 6);
            var date = val.substring(6, 8);
            var date2 = new Date(year+"-"+month+"-"+date);
            if(date2 && date2.getMonth() == (parseInt(month) - 1)) {
                return true;
            }
        }
        return false;
    }
    var checkProv = function (val) {
        var pattern = /^[1-9][0-9]/;
        var provs = {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"};
        if(pattern.test(val)) {
            if(provs[val]) {
                return true;
            } 
        }
        return false;
    }
    var checkID = function (val) {
        if(checkCode(val)) {
            var date = val.substring(6,14);
            if(checkDate(date)) {
                if(checkProv(val.substring(0,2))) {
                    return true;
                }
            }
        }
        return false;
    }
    //输出 true
    console.log("11010519491231002X : "+checkID("11010519491231002X"));
    //输出 false，校验码不符
    console.log("110105194912310021 : "+checkID("110105194912310021"));
    //输出 false，日期码不符
    console.log("110105194902310026 : "+checkID("110105194902310026"));
    //输出 false，地区码不符
    console.log("160105194912310029 : "+checkID("160105194912310029"));
</script>
</body>
</html>