js，身份证校验(正则表达式)

做这个其实不难,在网上多找一下总会有意外收获的.但是工欲善其事,必先利其器.我们需要了解一下身份证号的规则,知己知彼百战不殆。

身份证号有15位和18位长度两种，15位的时候，都是数字，但是18位长度的时候可能有校验位(X)，所以只校验数字是不够的了。

另外身份证号可以看出一个人的年龄，出生所在地（身份证所在地？）等等，这些对我们来讲都是有用的数据。
```javascript

/*
Author:yufulong
Blog:http://www.xiaoxiaozi.com
*/
var vcity={ 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"
};

checkCard = function()
{
var card = document.getElementById('card_no').value;
//是否为空
if(card === '')
{
alert('请输入身份证号，身份证号不能为空');
document.getElementById('card_no').focus;
return false;
}
//校验长度，类型
if(isCardNo(card) === false)
{
alert('您输入的身份证号码不正确，请重新输入');
document.getElementById('card_no').focus;
return false;
}
//检查省份
if(checkProvince(card) === false)
{
alert('您输入的身份证号码不正确,请重新输入');
document.getElementById('card_no').focus;
return false;
}
//校验生日
if(checkBirthday(card) === false)
{
alert('您输入的身份证号码生日不正确,请重新输入');
document.getElementById('card_no').focus();
return false;
}
//检验位的检测
if(checkParity(card) === false)
{
alert('您的身份证校验位不正确,请重新输入');
document.getElementById('card_no').focus();
return false;
}
alert('OK');
return true;
};

//检查号码是否符合规范，包括长度，类型
isCardNo = function(card)
{
//身份证号码为15位或者18位，15位时全为数字，18位前17位为数字，最后一位是校验位，可能为数字或字符X
var reg = /(^\d{15}$)|(^\d{17}(\d|X)$)/;
if(reg.test(card) === false)
{
alert("demo");
return false;
}

return true;
};

//取身份证前两位,校验省份
checkProvince = function(card)
{
var province = card.substr(0,2);
if(vcity[province] == undefined)
{
return false;
}
return true;
};

//检查生日是否正确
checkBirthday = function(card)
{
var len = card.length;
//身份证15位时，次序为省（3位）市（3位）年（2位）月（2位）日（2位）校验位（3位），皆为数字
if(len == '15')
{
var re_fifteen = /^(\d{6})(\d{2})(\d{2})(\d{2})(\d{3})$/;
var arr_data = card.match(re_fifteen);
var year = arr_data[2];
var month = arr_data[3];
var day = arr_data[4];
var birthday = new Date('19'+year+'/'+month+'/'+day);
return verifyBirthday('19'+year,month,day,birthday);
}
//身份证18位时，次序为省（3位）市（3位）年（4位）月（2位）日（2位）校验位（4位），校验位末尾可能为X
if(len == '18')
{
var re_eighteen = /^(\d{6})(\d{4})(\d{2})(\d{2})(\d{3})([0-9]|X)$/;
var arr_data = card.match(re_eighteen);
var year = arr_data[2];
var month = arr_data[3];
var day = arr_data[4];
var birthday = new Date(year+'/'+month+'/'+day);
return verifyBirthday(year,month,day,birthday);
}
return false;
};

//校验日期
verifyBirthday = function(year,month,day,birthday)
{
var now = new Date();
var now_year = now.getFullYear();
//年月日是否合理
if(birthday.getFullYear() == year && (birthday.getMonth() + 1) == month && birthday.getDate() == day)
{
//判断年份的范围（3岁到100岁之间)
var time = now_year - year;
if(time >= 3 && time <= 100)
{
return true;
}
return false;
}
return false;
};

//校验位的检测
checkParity = function(card)
{
//15位转18位
card = changeFivteenToEighteen(card);
var len = card.length;
if(len == '18')
{
var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);
var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');
var cardTemp = 0, i, valnum;
for(i = 0; i < 17; i ++)
{
cardTemp += card.substr(i, 1) * arrInt[i];
}
valnum = arrCh[cardTemp % 11];
if (valnum == card.substr(17, 1))
{
return true;
}
return false;
}
return false;
};

//15位转18位身份证号
changeFivteenToEighteen = function(card)
{
if(card.length == '15')
{
var arrInt = new Array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);
var arrCh = new Array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');
var cardTemp = 0, i;
card = card.substr(0, 6) + '19' + card.substr(6, card.length - 6);
for(i = 0; i < 17; i ++)
{
cardTemp += card.substr(i, 1) * arrInt[i];
}
card += arrCh[cardTemp % 11];
return card;
}
return card;
};
```