验证身份证号格式

//根据出生日期计算年龄
function ageByDate(str) {   
             var r = str.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);     
             if (r == null) {
                 return false;
             }
             var d = new Date(r[1], r[3] - 1, r[4]);     
             if (d.getFullYear() == r[1] && (d.getMonth() + 1) == r[3] && d.getDate() == r[4]) {   
                 var Y = new Date().getFullYear();   
                 return Y - r[1];   
             } else {
                 return false;
             }
         }
//验证身份证号格式
   function checkId(idcard) {
             var Errors = new Array("验证通过!", "身份证号码位数不对!", "身份证号码出生日期超出范围或含有非法字符!", "身份证号码校验错误!", "身份证地区非法!");
             var area = {
                 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"
             }
             var retflag = false;
             var idcard, Y, JYM;
             var S, M;
             var idcard_array = new Array();
             idcard_array = idcard.split("");
             //地区检验 
             if (area[parseInt(idcard.substr(0, 2))] == null)
                 return Errors[4];
             //身份号码位数及格式检验 
             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}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}$/; //测试出生日期的合法性 
                     } 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}$/; //测试出生日期的合法性 
                     }
                     if (ereg.test(idcard)) {
                         return Errors[0];
                     } else {
                         return Errors[2];
                     }
                     break;
                 case 18:
                     if (parseInt(idcard.substr(6, 4)) % 4 == 0 || (parseInt(idcard.substr(6, 4)) % 100 == 0 && parseInt(idcard.substr(6, 4)) % 4 == 0)) {
                         ereg = /^[1-9][0-9]{5}(19|20)[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}[0-9Xx]$/; //闰年出生日期的合法性正则表达式 
                     } else {
                         ereg = /^[1-9][0-9]{5}(19|20)[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则表达式 
                     }
                     if (ereg.test(idcard)) { //测试出生日期的合法性 
                         //计算校验位 
                         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); //判断校验位 
                         if (M == idcard_array[17])
                             return true; //检测ID的校验位 
                         else
                             return false; //Errors[3]
                     } else
                         return false;//Errors[2]
                     break;
                 default:
                     return false;//Errors[1];
                     break;
             }         }