js身份证号合法性验证

//js身份证号合法性验证
//支持15位和18位身份证号
//支持地址编码、出生日期、校验位验证

function IdentityCodeValid(code) {
 code = code.toUpperCase();
 var 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 "
 };
 var tip = "";
 var pass = true;

 if(!code || !/^\d{6}(18|19|20)?\d{2}(0[1-9]|1[012])(0[1-9]|[12]\d|3[01])\d{3}(\d|X|x)$/i.test(code)) {
  //if(!code || !/(^\d{17}(\d|X|x)$)/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
   var factor = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
   //校验位
   var parity = [1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2];
   var sum = 0;
   var ai = 0;
   var wi = 0;
   for(var i = 0; i < 17; i++) {
    ai = code[i];
    wi = factor[i];
    sum += ai * wi;
   }
   var last = parity[sum % 11];
   if(parity[sum % 11] != code[17]) {
    tip = "校验位错误";
    pass = false;
   }
  }
 }
 //if(!pass) mui.toast(tip);
 return pass;
}