js验证身份证号码

 function IdentityCodeValid(code) {
         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[12])(0[1-9]|[12]\d|3[01])\d{3}(\d|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]){
                     pass =false;
                 }
             }
         }
         return pass;
     }

注：属于转载