js验证身份证格式

<script language="javascript">
<!--
var powers=new Array("7","9","10","5","8","4","2","1","6","3","7","9","10","5","8","4","2");
var parityBit=new Array("1","0","X","9","8","7","6","5","4","3","2");
var sex="male";
//校验身份证号码的主调用

function validId(obj){
var _id=obj.value;
if(_id=="")return;
var _valid=false;
if(_id.length==15){
_valid=validId15(_id);
}else if(_id.length==18){
_valid=validId18(_id);
}
if(!_valid){
alert("身份证号码有误,请检查!");
obj.focus();
return;
}
//设置性别

var sexSel=document.getElementById("sex");
var options=sexSel.options;
for(var i=0;i<options.length;i++){
if(options[i].value==sex){
options[i].selected=true;
break;
}
}
}
//校验18位的身份证号码

function validId18(_id){
_id=_id+"";
var _num=_id.substr(0,17);
var _parityBit=_id.substr(17);
var _power=0;
for(var i=0;i< 17;i++){
//校验每一位的合法性

if(_num.charAt(i)<'0'||_num.charAt(i)>'9'){
return false;
break;
}else{
//加权

_power+=parseInt(_num.charAt(i))*parseInt(powers[i]);
//设置性别

if(i==16&&parseInt(_num.charAt(i))%2==0){
sex="female";
}else{
sex="male";
}
}
}
//取模

var mod=parseInt(_power)%11;
if(parityBit[mod]==_parityBit){
return true;
}
return false;
}
//校验15位的身份证号码

function validId15(_id){
_id=_id+"";
for(var i=0;i<_id.length;i++){
//校验每一位的合法性

if(_id.charAt(i)<'0'||_id.charAt(i)>'9'){
return false;
break;
}
}
var year=_id.substr(6,2);
var month=_id.substr(8,2);
var day=_id.substr(10,2);
var sexBit=_id.substr(14);
//校验年份位

if(year<'01'||year >'90')return false;
//校验月份

if(month<'01'||month >'12')return false;
//校验日

if(day<'01'||day >'31')return false;
//设置性别

if(sexBit%2==0){
sex="female";
}else{
sex="male";
}
return true;
}
//-->

</script>

<input text=""/>

<select id="sex">
<option value="male">男</option>
<option value="female">女</option>