話不多說，直接上程式碼，我不生產程式碼，我只是程式碼的搬運工。

//驗證身份證號方法
var test = function (idcard) {
    var Errors = new Array("驗證通過!", "身份證號碼位數不對!", "身份證號碼出生日期超出範圍或含有非法字元!", "身份證號碼校驗錯誤!", "身份證地區非法!");
    var area = {11: "北京", 12: "天津", 13: "河北", 14: "山西", 15: "內蒙古", 21: "遼寧", 22: "吉林", 23: "黑龍江", 31: "上海", 32: "江蘇", 33: "浙江", 34: "安徽", 35: "福建", 36: "江西", 37: "山東", 41: "河南", 42: "湖北", 43: "湖南", 44: "廣東", 45: "廣西", 46: "海南", 50: "重慶", 51: "四川", 52: "貴州", 53: "雲南", 54: "西藏", 61: "陝西", 62: "甘肅", 63: "青海", 64: "寧夏", 65: "xinjiang", 71: "臺灣", 81: "香港", 82: "澳門", 91: "國外"}
    var idcard, Y, JYM;
    var S, M;
    var idcard_array = new Array();
    idcard_array = idcard.split("");
    if (area[parseInt(idcard.substr(0, 2))] == null) return Errors[4];
    switch (idcard.length) {
        case 15:
            if ((parseInt(idcard.substr(6, 2)) + 1900) % 4 == 0 || ((parseInt(idcard.substr(6, 2)) + 1900) % 100 == 0 && (parseInt(idcard.substr(6, 2)) + 1900) % 4 == 0)) {
                ereg = /^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}$/;//測試出生日期的合法性
            }
            else {
                ereg = /^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}$/;//測試出生日期的合法性
            }
            if (ereg.test(idcard))
                return Errors[0];
            else
                return Errors[2];
            break;
        case 18:
            if (parseInt(idcard.substr(6, 4)) % 4 == 0 || (parseInt(idcard.substr(6, 4)) % 100 == 0 && parseInt(idcard.substr(6, 4)) % 4 == 0)) {
                ereg = /^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}[0-9Xx]$/;//閏年出生日期的合法性正則表示式
            }
            else {
                ereg = /^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}[0-9Xx]$/;//平年出生日期的合法性正則表示式
            }
            if (ereg.test(idcard)) {
                S = (parseInt(idcard_array[0]) + parseInt(idcard_array[10])) * 7 + (parseInt(idcard_array[1]) + parseInt(idcard_array[11])) * 9 + (parseInt(idcard_array[2]) + parseInt(idcard_array[12])) * 10 + (parseInt(idcard_array[3]) + parseInt(idcard_array[13])) * 5 + (parseInt(idcard_array[4]) + parseInt(idcard_array[14])) * 8 + (parseInt(idcard_array[5]) + parseInt(idcard_array[15])) * 4 + (parseInt(idcard_array[6]) + parseInt(idcard_array[16])) * 2 + parseInt(idcard_array[7]) * 1 + parseInt(idcard_array[8]) * 6 + parseInt(idcard_array[9]) * 3;
                Y = S % 11;
                M = "F";
                JYM = "10X98765432";
                M = JYM.substr(Y, 1);
                if (M == idcard_array[17])
                    return Errors[0];
                else
                    return Errors[3];
            }
            else
                return Errors[2];
            break;
        default:
            return Errors[1];
            break;
    }
}
//測試程式碼
var theid = prompt("請輸入身份證號碼", "15位或18位");
if (theid != "") {
    document.write(test(theid));
} else {
//theid=prompt("請輸入身份證號碼","15位或18位");
}