文本框中输入固定位数的字符串（字母+数字）后加逗号，求大侠帮助~
如题：下面代码是类似于在线支付时输入固定4位卡号后自动加空格，我想把正则的验证改成：输入固定10位字符串（大写字母+数字 的组合）后自动加逗号，求大侠帮忙！！！
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>test</title>
<script type="text/javascript">
window.onload =function() {
document.getElementById("test").onkeyup =function() {
this.value =this.value.replace(/\s/g,' ').replace(/(\d{4})(?=\d)/g,"$1 ");;
};
};
</script>
</head>
<body>
<input type="text" id="test"/>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>test</title>
<script type="text/javascript">
window.onload =function() {
document.getElementById("test").onkeyup =function() {
this.value =this.value.replace(/\s/g,' ').replace(/([0-9a-zA-Z]{10})(?=\d)/g,"$1 ");;
};
};
</script>
</head>
<body>
<input type="text" id="test"/>
</body>
</html>
window.onload =function() {
document.getElementById("test").onkeyup =function() {
this.value =this.value.replace(/[^0-9a-zA-Z]/g,'').replace(/(.{10})(?=.)/g,"$1,");
};
};
