<!DOCTYPE html>
<html>
<head>
<title>提取身份证号</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no"/>
</head>
<body>
<div id="one">
林芳德 30233212956620120x 男 26岁
李云飞 302332129566201201 女 30岁
龚丽芬 302332129566201202 男 28岁
王晋珺 30233212956620120X 男 20岁
</div>
<script type="text/javascript">
function getIDcard(string){
var reg=/[0-9,X,x]/;
var num = 0;
var IDarr = "";
var arr = string.split("");
for (var i = 0; i < arr.length; i++) {
var item = arr[i];
if(reg.test(item)){
num++;
IDarr += ""+item;
if(num == 18){
console.log(IDarr.toString())
}
}else{
num = 0;
IDarr = "";
}
}
}
var stringone = document.getElementById("one").innerHTML;
getIDcard(stringone);
</script>
</body>
</html>