**银行卡四位一空格代码**
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>充值兑换</title>
<meta name="viewport" content="user-scalable=no,initial-scale=1.0,maximum-scale=1.0,width=device-width">
<link href="__THEME__/css/reset.css" rel="stylesheet" type="text/css">
<script type="text/javascript" src="__THEME__/js/jquery.js"></script>
</head>
<body>
<div class="coupon">
<div class="content">
<form action="">
<p class="input_txt"><input type="text" id="duihuan" placeholder="请输入兑换码"></p>
</form>
</div>
</div>
<script type="text/javascript">
$(function(){
$('#duihuan').keyup(function(){
var value=$(this).val().replace(/\s/g,'').replace(/(\d{4})(?=\d)/g,"$1 ");
$(this).val(value);
});
});
</script>
</body>
</html>