使用数组、表单、字符串处理函数等实现功能： 1.输入身份证号码并获取身份证号码 2.判断身份证是否合法 2.1判断身份证位数是否是18位或是15位，否则不是合法身份证，重新输入 2.2判断身份证出身年月日是否合法 2.3判断省份位是否合法 3.获得身份证所属省份，出生年月日和性别信息。

1. 实现输入身份证号码并获取身份证号码：

<form>
    <input type="text" id="id_num" name="id_num" placeholder="请输入身份证号码">
    <button type="button" onclick="getID()">获取身份证号码</button>
</form>
<script>
    function getID() {
        var id_num = document.getElementById("id_num").value;
        alert("身份证号码：" + id_num);
    }
</script>

2. 实现判断身份证是否合法：

<form>
    <input type="text" id="id_num" name="id_num" placeholder="请输入身份证号码">
    <button type="button" onclick="checkID()">检验身份证合法性</button>
</form>
<script>
    function checkID() {
        var id_num = document.getElementById("id_num").value;
        var reg = /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/;
        if (reg.test(id_num) === false) {
            alert("身份证格式不合法，请重新输入");
            return false;
        }
        alert("身份证格式合法");
        return true;
    }
</script>

3. 实现获得身份证所属省份、出生年月日和性别信息：

<form>
    <input type="text" id="id_num" name="id_num" placeholder="请输入身份证号码">
    <button type="button" onclick="getID()">获取身份证信息</button>
</form>
<script>
    function getID() {
        var id_num = document.getElementById("id_num").value;
        var reg = /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/;
        if (reg.test(id_num) === false) {
            alert("身份证格式不合法，请重新输入");
            return false;
        }
        var province = {
            11: "北京市",
            12: "天津市",
            13: "河北省",
            14: "山西省",
            15: "内蒙古自治区",
            21: "辽宁省",
            22: "吉林省",
            23: "黑龙江省",
            31: "上海市",
            32: "江苏省",
            33: "浙江省",
            34: "安徽省",
            35: "福建省",
            36: "江西省",
            37: "山东省",
            41: "河南省",
            42: "湖北省",
            43: "湖南省",
            44: "广东省",
            45: "广西壮族自治区",
            46: "海南省",
            50: "重庆市",
            51: "四川省",
            52: "贵州省",
            53: "云南省",
            54: "西藏自治区",
            61: "陕西省",
            62: "甘肃省",
            63: "青海省",
            64: "宁夏回族自治区",
            65: "新疆维吾尔自治区",
            71: "台湾省",
            81: "香港特别行政区",
            82: "澳门特别行政区"
        };
        var year = "";
        var month = "";
        var day = "";
        var sex = "";
        if (id_num.length === 18) {
            year = id_num.substr(6, 4);
            month = id_num.substr(10, 2);
            day = id_num.substr(12, 2);
            sex = id_num.substr(14, 3) % 2 === 0 ? "女" : "男";
        } else {
            year = "19" + id_num.substr(6, 2);
            month = id_num.substr(8, 2);
            day = id_num.substr(10, 2);
            sex = id_num.substr(12, 3) % 2 === 0 ? "女" : "男";
        }
        var province_code = id_num.substr(0, 2);
        var province_name = province[province_code];
        var message = "省份：" + province_name + "\n出生年月日：" + year + "年" + month + "月" + day + "日\n性别：" + sex;
        alert(message);
        return true;
    }
</script>